Off-road racing's George Antill, 76, has passed away. He is remembered as the voice and one of the driving forces behind SCORE International's modern era.
Known for his passionate voice and deep connection to the community, Antill served as the "official voice" of SCORE from 2013 to 2015, conducting thousands of interviews at race starts and finish lines across the U.S. and Mexico.
A former racer himself, Antill got his start on motorcycles in California in the late 1960s. He later became the executive producer and host of Dirt Live, an internet show that brought off-road stars—and SCORE International itself—to a broader audience. His appointment as SCORE's public face came shortly after Roger Norman acquired the organization in 2012, marking a new chapter in off-road media and fan engagement.
"All of us in the SCORE family are deeply saddened by the loss of George," said SCORE President and Race Director Jose A. Grijalva. "We extend our heartfelt condolences to his family and friends... Rest in peace, my friend."
'Champ' and 'Turbo' will be available 24/7 to answer any questions about attending and exhibiting at the PRI Show, offering a powerful new resource to maximize ROI.
PRI is introducing a brand-new resource for PRI Show attendees and exhibitors this year, adding another valuable tool to help Showgoers maximize their time at the 2025 PRI Show, December 11-13, Indianapolis, right at their fingertips.
Officially launched on prishow.com/attend and prishow.com/exhibit, the new "Turbo" and "Champ" AI chatbots provide attendees and exhibitors with a new way to access all pertinent Show information.
Both available anytime, anywhere, Turbo will assist with all attendee-related questions and can help you make the most of your time at the PRI Show.
Champ, the AI chatbot for exhibitors, will be there night and day to provide all the information you need to have a successful PRI Show, and will answer any questions, direct you to available resources and a lot more, allowing you to focus on striking new deals, finding new customers and further establishing your brand on the motorsports landscape.
Plus, Turbo and Champ will learn as they develop, expanding their expertise based on questions asked by PRI Showgoers. Make the most of your PRI Show planning and get to know Turbo or Champ on prishow.com today!
Turbo and Champ are just a few of the many resources available throughout the PRI Show. See some of those Show resources below:
Attendee registration for the 2025 PRI Show opens Tuesday, July 15. Click here for more information. PRI membership is required to attend the PRI Show.
PRI Show exhibitor registration is now open here. Click here for more information, or to register your company personnel and booth workers. New for 2025, exhibitors can access registration through their Exhibitor Resources dashboard. Click here to visit PRI 2025's Map Your Show.
Get ready to book your tickets for Indianapolis because attendee registration for the 2025 PRI Show, December 11-13, opens for qualified industry members on Tuesday, July 15.
This year's event will once again offer an experience unlike any other trade show on the planet, delivering the three biggest business days of the year for the global motorsports community and the backdrop of all the newest racing parts, products and services from thousands of industry suppliers.
With a focus on the present and future of racing, the 2025 PRI Show promises to feature all the newest parts, latest innovations, nearly unlimited networking opportunities and access to an unrivaled number of motorsports manufacturers and service providers that can't be matched anywhere else. Attendees can also get excited for some of the Show's signature events and features, including the Featured Products Showcase, the Grand Opening Breakfast (keynote speaker set to be announced at a later date), the world-famous Machinery Row with live demonstrations, the PRI ESports Arena and much more.
You can also view the current 2025 PRI Show Floorplan here. Check back in during the leadup to the Show to see what other motorsports brands are added to the world's largest gathering of motorsports professionals.
Before registering, PRI Show organizers recommend attendees book their hotel rooms now to start planning the best PRI Show experience possible. Click here to secure your accommodations.
In addition, prospective attendees should also renew their PRI Membership, which is required to attend the Show.
For more information on the 2025 PRI Show, visit here.
Scribner Plastics--the family-owned and operated rotational molding company specializing in reusable shipping containers, barrier systems, and engine and transmission shipping containers--has announced its relocation from Rancho Cordova, California, to Victoria, Texas.
The long-planned relocation is intended to be more centrally located to their customer base, as well as closer to the Houston shipping port for their export customers, according to a company release.
Scribner Plastics acquired a five-acre industrial parcel to build a duplicate factory with room for future expansion. A new Ferry Industries rotational machine has been installed, with additional machinery being shipped from California to Texas.
Current employees were offered relocation incentives, according to Scribner Plastics.
One of the PRI Show's most impactful traditions is back for 2025: the Hot Rodders of Tomorrow National Championship. Watch from Wednesday, December 10 through Saturday, December 13, as elite high school teams from across the country tear down and reassemble engines in a high-speed, high-pressure competition that showcases the next generation of racing industry professionals.
Qualifying student teams from across the U.S.—including the Top 4 coming from the 2025 SEMA Show—will face off in a bracket-style showdown, with Wednesday and Thursday narrowing the field for the Elite Eight rounds on Friday and Saturday.
Since its founding in 2008, the Hot Rodders of Tomorrow has awarded millions in scholarships and inspired thousands of young people to pursue careers in motorsports and performance. For many in the industry, it's a must-see highlight of PRI Week—and a powerful reminder of why we should invest in the future of motorsports.
For more information, including how your company can participate in this exclusive event, visit hotroddersoftomorrow.com.
🔧 Hot Rodders of Tomorrow at PRI 2025🔧
Wednesday, December 10 - Saturday, December 13
🗓️ Don't forget: PRI Show attendee registration opens on Tuesday, July 10! Book your hotel now through the official PRI Show block online here, and start mapping out your visit to the world's largest gathering of motorsports professionals with the 2025 PRI Show Planner.
PRI cares about your four-legged pit crew! PRI Individual Members receive 70% off your first purchase at The Farmer’s Dog, the subscription service offering freshly made pet food tailored to your dog’s needs, delivered straight to your door. Claim your discount code now through your PRI Member Portal.
PRI is not affiliated with, nor does it sell or thoroughly evaluate the products, services, and companies listed. PRI provides this information to PRI members for their evaluation and consideration and does not endorse or sponsor any company, product, or service. PRI takes no responsibility for, and makes no representation, warranty, or assurance as to the accuracy, quality, reliability, or completeness of the products or services offered.
Motorsports is more than a sport—it’s a thriving ecosystem powered by innovation, competition, passion, and community. At Performance Racing Industry (PRI), our mission is to connect, protect, and advocate for this ecosystem and all who make it possible.
Fresh insights from our first-ever economic impact report tell a compelling story: motorsports plays a vital role in driving economic activity, supporting American jobs, and strengthening local communities nationwide, contributing more than $68.7 billion annually to the American economy (turn to page 14 for more information).
Since joining PRI in February 2024, I’ve made it a priority to continuously listen and learn from our community to better understand the evolving state of our industry. I’ve been visiting tracks, meeting with sanctioning bodies, engaging with members and customers, and participating in advocacy events. These ongoing conversations continue to shape our perspective and guide our efforts. They inform a strategic roadmap rooted in real-world insight—one that strengthens the foundational pillars of motorsports while driving us toward a more resilient and thriving future.
One of our key priorities is strengthening relationships with the sanctioning bodies that form the foundation of organized racing. These organizations are the rule-makers, safety leaders, and cultural stewards of motorsports. Whether it’s grassroots dirt track or professional-level road racing, PRI is actively working to align with sanctioning bodies to support growth, consistency, and shared success across the industry.
We’re also focused on supporting the 1,260-plus race tracks (source: National Speedway Directory) across the United States. These venues aren’t just places where racing happens—they’re economic drivers and community hubs. PRI is committed to advocating for track owners and promoters, especially as they face increased challenges with zoning, environmental regulation, and operational sustainability. We are ensuring their voices are heard in legislative arenas and working to provide resources to help them thrive.
Looking ahead, the future of motorsports depends on who we invite into it. That’s why PRI launched the Next Generation Initiative, aimed at connecting with vocational schools and higher education institutions to introduce students to the diverse careers available in racing. From engineering and fabrication to media and business, we’re building partnerships that will expose students to the opportunities motorsports offers—and inspire them to make their mark.
And of course, the PRI Show remains a cornerstone of our mission. As the industry’s premier business gathering place, it continues to evolve in shape and scope to deliver maximum value for exhibitors, attendees, and the global racing community. We’re reimagining how the Show can best serve as a launchpad for innovation, a hub for business development, and a celebration of everything motorsports stands for.
These focus areas are more than individual initiatives—they are part of a larger vision to safeguard and grow the industry we love. By building bridges between sanctioning bodies, supporting the grassroots tracks that keep racing alive, and investing in future talent, PRI is taking bold steps to ensure motorsports remains strong for generations to come.
We’re proud of the work being done—and we’re just getting started.
Michael Good
President
Performance Racing Industry
Mark Williams Enterprises in Louisville, Colorado, offers its "Ultimate" 9-in. Ford rearend assembly that is manufactured from an aerospace alloy aluminum, which company sources report is 30% more durable than the commonly used 6061 aluminum.
Performing all CNC machining in-house, the modular design incorporates a selection of end bells that determine the housing's width. For both four-link and solid installations, mounts are available with either flanged or full-floater axels. In addition to the mounts, steel tubes are available for street applications.
M-W's "Ultimate Hi-Torque" axles are made of 300M material and are backed by a 10-year warranty against breakage. Finishing the "Ultimate" assembly are special 10-in. pitch diameter ring and pinion gears, made in collaboration with Gleason Corp. Designed for high-horsepower applications, these are made from 9310 alloy, precision ground, shot-peened, REM micro-polished and sub-zero treated.
Hot Shot's Secret in Mt. Gilead, Ohio, now offers two new multi-purpose extreme pressure organoclay-based greases: 7460EP and 7150EP. This uniquely compounded solubilized molybdenum (moly) provides a bleed-resistant grease that's infused with rust and corrosion inhibitors with antioxidant additives that provide a higher level of tackiness for longer-lasting performance.
The 7150EP is ideal for high-speed automotive applications in parts such as wheel bearings that need to withstand the dynamic forces of thrust, radial loads and overall smooth and enduring operation. The 7460EP is ideal for press section bearings, machine bearings or any machine bearings that require a more viscous, robust grease that can withstand extreme pressures and heavier loads. Hot Shot's Secret's 7000 series EP grease was engineered to deliver performance in demanding conditions and can tolerate extreme heat, cold, or moisture.
Available in 7- or 10-inch sizes, the FiTech-One Gauge LCD touchscreens from FiTech Fuel Injection in Riverside, California, were designed to seamlessly integrate with FiTech EFI systems. FiTech's customizable touchscreen allows users to design personalized screen layouts to create a display that fits their unique setup. These new displays deliver a highly accurate, low latency, adaptable interface that can accommodate a wide range of sensors to ensure user-friendly flexibility for all types of enthusiasts.
The One Gauge LCD kit can monitor critical engine and vehicle parameters, including rpm, engine load, MAP, coolant temps, oxygen sensor AFR, and much more. The CNC-machined, black anodized aluminum housing offers splash-proof protection with rear flush mounting patterns and flexible wiring options. This highly modular display kit allows for expandability so users can easily add features like lap timing, shift lights and datalogs. The GPS speedometer will also include compass direction, altitude, and location data without requiring any physical connections.
The New IMCA Modified spec racing engine (#12135503) from Speedway Motors Racing Engines, located in Lincoln, Nebraska, produces more power and torque than a 604-crate engine while maintaining drivability. In addition to the impressive power and torque ratings, the new IMCA Modified spec engine is an unsealed crate motor that utilizes low-maintenance hydraulic roller cams—providing racers the freedom to maintain their engine throughout a race season. Each engine uses a 3.480-in. stroke stock-appearing steel crankshaft, IMCA-approved SCAT Pro-Series connecting rods, and forged flat-top pistons yielding the required 9.0:1 compression ratio.
Each engine is topped with an MSD Pro Billet distributor and the IMCA Modified spec required Edelbrock 2975 Victor Jr. single plane intake manifold. The displacement is 355–360 cubic inches, paired with Dart IMCA-approved cast iron cylinder heads and a steel 7-quart oil pan with IMCA-required 1-in. inspection plug. Lastly, each engine is broken in on a dyno with a proprietary program and tuned for the use of methanol fuel only, producing a solid race engine that promotes power and reliability.
PPE CRANKCASE VENTILATION OIL/WATER SEPARATION KIT
Pacific Performance Engineering (PPE) in North Las Vegas, Nevada, launches its new PPE crankcase ventilation oil/water separation Kit for 2020–2025 GM 3.0L DURAMAX. PPE, concerned with optimizing engine efficiency and longevity, tackled the oil and hydrocarbon emissions that are vented through the crankcase ventilation system, and redirected into the turbo compressor housing. Contaminants tend to mix with EGR gases, leading to harmful buildup in vital components like the intake manifold, swirl valves, and intake valves. The Crankcase Ventilation Oil/Water Separation Kit aims to combat reduced performance, poor fuel economy, elevated EGTs, compression loss, increased emissions, and the impact of potential damages seen on other vital engine components found in extended periods of contamination accumulation.
The high-quality PCV hoses are oil-resistant, reduce mixture velocity, enhance condensation of oil, hydrocarbons and water vapor. Through a stainless-steel mesh screen, the advance filtration system effectively captures the oil, hydrocarbons, and water vapor, preventing these contaminants from re-entering the system. The aluminum oil reservoir is engineered to fit securely above the fender liner and has an easily accessible drain hose for user convenience.
To read the complete article for free, sign up for a digital subscription to PRI Magazine on Zinio here.
Once you download the Zinio mobile app or are logged into Zinio on a desktop browser, you will gain immediate access to more than a year's worth of content, including "Race Shop: New Racing Parts and Products" here and more road racing coverage in the July 2025 issue here.
The race is on to build cylinder heads to handle more boost. Several manufacturers explain just how they are overcoming the current challenges.
Tony McAfee from Dart Machinery was at the Texas Motorplex earlier this year for TX2K, billed as the “super bowl of street car events” and where drag racing is the focus.
He noticed something that speaks to a continuing trend in the high-performance and motorsports industries. “I don’t think there was a naturally aspirated car on the grounds,” he said.
With more street enthusiasts and racers seeking a boost from nitrous oxide, superchargers, or turbochargers, cylinder head manufacturers are among those taking notice.
While the effect of power-adders on head development isn’t new, it is “heavily, heavily accelerated,” McAfee added.
“I think the trend is power adder.”
Certainly, the contacts we made for this story, including Dart in Warren, Michigan, would support that theory. All of them have recent news regarding cylinder heads for boost.
Upgraded internal parts and materials help cylinder heads survive the extreme pressures of boosted applications. Frankenstein Engine Dynamics has developed the Monster, Boost Monster, and Boost Monster Plus lines of cylinder heads for such applications.
“The industry across the board is moving to mostly boosted applications,” said Jesse Meagher of Frankenstein Engine Dynamics, Weatherford, Texas. “There aren’t as many naturally aspirated engines out there because they might cost twice as much and make half the horsepower. That’s a hard argument to make.”
From circle track to road racing, and especially drag racing, we take a case by case look at what some of the biggest names in cylinder heads are building for boost.
Design Difference
Jamie Wagner of Edelbrock in Olive Branch, Mississippi, said racers using boosted applications are asking more of their cylinder heads, in particular larger valves—especially intake—and larger port sizes.
“Bigger, better designed exhaust ports allow the spent gases to be pushed out of the cylinder more completely, resulting in a better environment inside the cylinder to allow the increased volume of air and fuel to enter,” he explained.
Wagner said boosted applications require more focus on volume in the runners than port design. “Boosted engines can overcome some of the issues in cylinder heads that would be detrimental to a normally aspirated application.”
Wagner reported that Edelbrock’s Victor CNC-ported LS7, LS3, and Gen III Hemi heads are “well suited for boosted applications.”
Victor heads are designed to maximize airflow into and out of the engine with large port volumes, but also with appropriate cross-sectional areas to ensure efficient flow.
Added boost or pressure comes at a price, Wagner noted, with additional parasitic drag on the engine in the case of a supercharger, and higher exhaust back pressures in the case of a turbo.
However, “a well-designed cylinder head allows more airflow into and out of the cylinder, which can give an increase in volumetric efficiency without the cost of increased inlet pressures. [It can] increase the overall power output with lower boost pressures,” Wagner said in discussing the Victor line.
It is important that some design features cross over from normally aspirated to boosted applications to retain good performance and drivability in off-boost conditions, such as idle and off-idle-to-boost transition, Wagner noted.
Built for Boost
Stronger materials like aluminum alloys, thicker deck surfaces to improve structural integrity and gasket retention, and enhanced heat resistance to prevent warping and cracking under extreme conditions are all characteristics of cylinder heads for boosted applications, according to Mark Ward from Air Flow Research (AFR) in Valencia, California.
Also, designs often incorporate better water-jacketing and cooling passages to manage increased heat, and port designs are refined to maximize airflow and fuel mixture. “These features collectively ensure that the cylinder heads can withstand the demanding conditions of high-performance boosted engines,” Ward said.
AFR’s 100% CNC-ported 224cc Black Hawk Gen III Hemi aluminum cylinder heads are outfitted with a 0.750-inch thick head deck that enhances overall strength and rigidity, Ward said.
Also, “we have improved the water-jacketing for enhanced cooling while retaining a minimum of 0.200-inch port-to-water-jacket thickness,” he added.
AFR also offers a Black Hawk Gen III Hemi as-cast head with 185cc intake runners and 69cc combustion chambers for the 5.7/6.1 platform. That version also has the same head deck and port-to-water-jacket thicknesses.
One of AFR’s newest heads is a 200cc intake/69cc combustion chamber complete as-cast version for the small block Chevy. “They come fully assembled with the identical components found in our higher-end CNC ported cylinder heads,” Ward said, noting things such as ARP rocker arm studs and stainless steel valves.
Head Hunting
The Head Hunter Series from Brodix in Mena, Arkansas, is the ideal product for this topic, reported Mark Fretz. “That’s the most popular head right now for a conventional [24-degree], cast-style, boosted application” in many drag racing classes, he said.
Fretz noted that while cast is not as durable as billet, “with all the advanced technology we have in the casting, the HIP-ing [hot isostatic pressing] process that we do, they’ve come a long way. We have guys who run a ton of boost [up to high-50s in pounds].”
Fretz noted the Brodix Ported Head Hunter Big Block (BP HH BB) 395 MC is also made with a special exhaust port, adding an “X” to its product ID—and a lot of power to the engine.
“That combination of cylinder head is well into the 3,000-horsepower range at the hub,” Fretz said, noting its use in radial tire drag classes and grudge racing.
One step under the Head Hunter is the BP BB 3-Xtra 380, which Fretz stated is popular in NHRA Top Dragster. “It’s an index class that can only run so fast, so you don’t need as much power,” he said.
As for a step above the Head Hunter, that’s the Sonny’s Design (designed by engine builder Sonny Leonard) 14 1/2 degree BP PB 2002. Popular in power-adder applications, it has a conical or “softened” combustion chamber that widens the tuning window for the head.
“That is a cylinder head that will flow right at 600 cfm, and it is the top head that we have,” Fretz explained.
Boost Monsters
Meagher at Frankenstein Engine Dynamics further discussed differences between boosted and naturally aspirated applications and how they manifest in the cylinder head.
“With a naturally aspirated setup, it’s often important to have a particular control over the exhaust flow,” he said. “But when you get into a boosted application, especially turbocharging, the reality is it’s just about getting it out—just get that gas out and spin that turbine, and away you go.”
The increased pressures of a boosted application make engine material and component choices vital, Meagher stressed, “to let it survive the performance we’re able to unlock.”
Frankenstein is building off its budget-minded Monster Series cylinder heads with a line of Boost Monster and Boost Monster Plus heads. Its M311 and M712—Monster versions of its LS3 and LS7 heads with 11- and 12-degree valve angles, respectively—have been upgraded to Boost Monster status with CHE bronze guides, Inconel exhaust valves, and upgraded port-flow characteristics.
Also, the M311 has a Boost Monster Plus version, which has a larger intake port along with the CHE bronze guides and Inconel exhaust valves, and a Plus version is coming for the M712 later this year. “It’s a really nice little package,” Meagher said.
Frankenstein’s cathedral port LS1 head, the M115, will also have Boost Monster and Boost Monster Plus iterations later this year, he added.
Most Monster head sales were going to drag racers, but that has expanded to include drifters, road racers, and sports cars, plus classic car, show car, and restoration builders. “With the Monster series, it’s at a price point and a performance level that really makes it a lot more viable to other applications,” he noted.
Boost Specific
Dart made “extreme exhaust port modifications” to its Big Chief 2 and Big Chief 3 cylinder head lines for boosted applications. The company also released a power-adder exhaust port option for its 380 Pro2 24-valve big block head earlier this year. Both lines are “specifically designed and marketed to the power-adder guys,” McAfee said.
While the effect of power-adders on cylinder head development isn’t new to report, it is “heavily, heavily accelerated,” reported to Tony McAfee of Dart Manufacturing. In fact, he added, “I think the trend is power adder,” and Dart has responded with several heads for boosted applications.
The goal is to achieve better blow-off when the exhaust valve opens to handle the extra air and fuel found with nitrous oxide, supercharged, or turbocharged applications. “As we modify the exhaust port or go larger at the exit side, it always tends to make better power and equate to a better ET,” he said.
The Pro2, meanwhile, is designed for big-displacement engines turning up to 7,500 rpm. It’s used in bracket racing, heads-up, and super classes and is billed as a more cost-effective version of Dart’s Race Series casting.
Dart also has a new version of its 10-degree canted-valve LS head, which McAfee said flows 500 cfm at the intake—matching with a small block what the Big Chief big block did five years ago.
“It’s more for either big cubic-inch stuff or big cubic-inch supercharger, turbocharger, nitrous applications,” he said about uses in drag, road racing, and circle track.
When it comes to LS engines, McAfee said, naturally aspirated, big-cubic-inch setups have become rare. “It’s power-adder one direction or another.”
Solid Change
All Pro Aluminum Cylinder Heads in Johnstown, Ohio, has been doing “an awful lot” of solid cylinder heads—with no water jackets—for methanol-powered drag cars. They are based on All Pro’s LSW-12-4 or LSW-12-5 heads. “[It] seems to be unlimited in what you can do with those,” Robert Williams said.
Numerous developments have been introduced in cylinder heads for boosted applications, including the 12-4 version of the All Pro Aluminum Cylinder Heads LSW Series of symmetrical port cylinder heads, this one with hoops sealing at the block.
Cars are towed to the starting line and from the finish line, but otherwise there’s no need to rush the cool-down. It does help that methanol burns cooler than gasoline. “When you get to the end you might still be only 140 degrees, so it’s not a big deal,” he said.
The solid head opens options for port design—but bigger isn’t always better. “The turbo stuff actually tends to like smaller ports in a lot of applications. And the supercharger’s the opposite—it likes a big port,” Williams explained. “They’re two totally different animals.”
Another benefit of the solid head: “Just brute strength.”
Overall, Williams described All Pro’s LSW Series of symmetrical port heads as “stout” and able to withstand a lot of cylinder pressure—up to 3,500 hp in some applications.
The use of larger head bolts and their placement toward the spark plug side—where LS engines tend to blow head gaskets with 8-mm factory bolts—is important. “[It] helps clamp the head better onto the block, under extreme conditions, without distorting the cylinder wall,” he said.
Cast-iron Strength
World Products in Louisville, Kentucky, known for its cast-iron heads, is selling some ported versions for boosted applications in marine, pulling, and street markets.
Iron holds up better for saltwater marine applications in particular, where larger boats may use three supercharged big block engines. “And they’re more durable, stronger,” Jack McInnis said about cast-iron powerplants.
Salt corrosion, durability, or, more simply, rules, are reasons someone chooses cast-iron over aluminum, reported McInnis.
As to porting cast-iron, it’s a little slower than cutting aluminum, he said, but some of the same airflow improvements can be achieved.
New Design, Same Wisdom
McInnis said “power-adder stuff” is indeed prevalent, especially in drag racing. “So people are making design changes to accommodate that or to suit it—things like adding strength, adding deck thickness, adding material in places where it’s more prone to be distorted or damaged.”
He explained that engine building wisdom has always been that when using forced induction, it forgives a lot in the cylinder head. But don’t be complacent, he cautioned. “If you’ve got a hot street motor and you stick a blower on it, it’s going to definitely pick it up. But if you’re in a class where everybody’s running boost, then the guy with the better setup is going to be faster.”
Lessons From Diesel
Matt Ryce of D&J Precision Machine in Cambridge, Ohio, cited the power of diesel when talking about one of the full-billet Cummins engines the company designed for the fellow horsepower-crazed Ohioans at Firepunk Diesel.
“I don’t even know if we can call it a diesel engine,” he joked. “It burns more nitrous.”
Developments in diesel boosted applications, such as a six-cylinder billet engine with 12 exhaust ports, could influence boost in gasoline engines, according to Matt Ryce at D&J Precision Machine.
The serious point is that the diesel market knows a thing or two about big boost. D&J has developed cylinder heads—such as the one in Firepunk’s sub-4-second (in the eighth-mile) Duster—to withstand massive cylinder pressures.
“We’re in a much different world than the gas side in that 100 pounds of boost is normal. I’ve heard people go as high as 190,” he said. “It really comes down to having the strength to withstand it.”
D&J upgrades 6.7-liter Cummins diesel engines for drag racing applications with its Stage 3 and 4 Cummins Performance Heads. Stage 3 has a billet intake manifold, oversized super alloy intake and exhaust valves, titanium valve spring retainers, heavy-duty extra-large intake seats and thread-in soft plugs. Stage 4 has those features plus a billet runner style intake manifold and reusable O-ring seals.
Stage 3 and 4 units start with factory cast Cummins steel heads, Ryce said, because they can better withstand porting and are more consistent than aftermarket heads.
Ryce noted diesels will produce peak cylinder pressures higher than those of a Top Fuel dragster, if for a shorter period of time. “So it’s important to have the quality of the components and the strength to handle that sort of cylinder pressure,” he explained.
Ryce said more interaction between the diesel and gas worlds is possible as it relates to cylinder heads, including with direct-injection technology. “I see a big connection with all the new direct-injection stuff, because with diesels we’ve been doing that for years. Can they use some of the things we’ve learned in our direct-injection systems?” —Andy Heintzelman
Is Big Block Back?
Dart Machinery in Warren, Michigan, is in the process of revamping its Pro1 Big Block Chevy CNC ported line, with “very significant gains” in airflow numbers and lift range.
The reason for the upgrade is that Dart sees a “large resurgence” in big block Chevy applications on the street and strip, Steve Rhodey said.
“It’s almost dominating our tech lines right now over LS or small block Chevy, small block Ford,” he said in March.
Why?
“I don’t know if the new school is starting to fall in line with the old school,” Rhodey answered, “and realizing that they can make big power for probably a lot less money than some of the high-end LS stuff.” —Andy Heintzelman
To read more like this, sign up for a digital subscription to PRI Magazine on Zinio here.
Once you download the Zinio mobile app or are logged into Zinio on a desktop browser, you will gain immediate access to more than a year's worth of content, including"Bigger and Bolder: Motorsports Cylinder Heads" story here and more road racing coverage in the July 2025 issue here.
The Della Penna Foundation invited a group of 34 high school girls from Indianapolis to learn more about careers in the motorsports industry during a three-day program during the Indianapolis 500 qualifying weekend.
Over the three-day itinerary, the participants visited the Indianapolis Motor Speedway, motorsport engineering giant Dallara, FastTimes Karting and the PRI headquarters in Speedway, Indiana, to learn about various careers in motorsports and hear directly from individuals who have experience working in racing.
The girls were exposed to a wide range of careers as they imagined and planned their futures, including a brunch hosted by PRI and Bell Helmet that featured presentations from experienced industry professionals Nicole Clark, Kai Robertson, Lyn St. James, Marilyn Mangin, Whitney Fung, AJ Carney, Cindy Sisson, Terri Talbert-Hatch, Lindsey Hennig, Nina Rey, Lauren Gaudion, TaiJaune Robinson, Meghan Ryder and many more.
You can read more about the Della Penna Foundation brunch at PRI HQ here.
Founded by Michelle Della Penna, daughter of the late race car driver and Indy car team owner John Della Penna, the Della Penna Foundation provides girls aged five to 18 with the knowledge, skills and mentorship to fuel a bright future in motorsports. At an age when girls drop out of STEM and sports, the foundation opens doors for them in the $7-billion motorsports industry.
"We are delighted by Bell Helmets' and PRI's support of the Della Penna INSPIRE 25 program, allowing us to make an impact on the lives of these young women," Della Penna said. "The funds raised from the silent auction of Bell racer-signed mini helmets at the PRI open house will be used for other hands-on events, and the brunch was an inspiring educational and networking experience. We are also grateful to Lisa Boggs and Firestone for their generous contribution to offset the costs of the INSPIRE program."
"We are thrilled to support the Della Penna Foundation alongside PRI, to show young women the many and varied opportunities in our industry. Della Penna Foundation is the only one that gives high school girls hands-on experience in the world of motorsports," said Lindsey Hennig, sales and marketing manager for Racing Force Group, the parent company of Bell Helmets.
"We're proud to partner with Bell Racing Helmets in hosting the Della Penna Foundation Inspire Program," said Michael Good, president of PRI. "Supporting opportunities that empower young women in motorsports aligns perfectly with PRI's mission to support an inclusive industry."
In 2025, the foundation is also offering karting scholarships and summer fellowships. To learn more, donate or sponsor, visit dellapennafoundation.org.
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