With Trans Dapt’s plastic and canvas phenolic carburetor spacers with Swirl-Torque technology, enthusiasts have a way to simultaneously fight back against the effects of excess heat buildup, while significantly boosting torque and horsepower. Trans Dapt’s insulated carburetor spacers are developed to provide excellent protection from heat soak and power loss caused by vapor lock and percolation. The phenolic materials used to make these carb spacers is a poor conductor of heat and it acts as a thermal barrier, isolating the carburetor from the heat of the engine, keeping the fuel mixture cool and dense. Without a thermal barrier, heat builds up in the carburetor and will eventually cause the fuel inside to boil. If this happens while the motor is running, it creates a loss of feed pressure to the carburetor which can then lead to a loss in power, or cause the engine to stall (vapor lock). However, when this happens after the engine has been turned off, the fuel can boil over out of the float chamber and leak into the intake manifold (percolation) making it hard, if not impossible, to restart the engine. Trans Dapt’s spacers with Swirl-Torque Technology are manufactured with a unique, slotted port design that creates a powerful vortex. This vortex atomizes the fuel for a better air/fuel mixture. The result is improved low to mid-range torque through improved combustion efficiency; better drivability and throttle response from your vehicle; and quicker shift recovery rates. Trans Dapt’s Swirl-Torque style phenolic carburetor spacers are manufactured in the USA using top of the line thermal resistant plastic or canvas material. Plastic phenolic spacers are available in ½ inch (Part# 2528), one inch (Part# 2529, 2531) and two inch (Part# 2530, 2532) thicknesses for Holley Square Bore Four Barrel carburetors with or without positive crank case ventilation (PCV). Canvas phenolic spacers are available in a one inch thickness for Holley Aluminum Four Barrel (AFB) carburetors, also with or without a PCV valve (Part # 2550, 2551).