The International Motor Contest Association (IMCA) has approved a rules amendment allowing both 602 and 604 crate engines to be overbored during authorized major repairs using approved MAHLE pistons and Total Seal rings, effective immediately.

The rules change provides racers with an additional repair option while maintaining the integrity of the crate engine program. All repairs must continue to be completed by an IMCA Authorized Repair Center and must comply with IMCA's existing crate engine repair procedures and sealing requirements.

The following aftermarket replacement components are approved for use during authorized IMCA major repairs:

• Mahle 602 Pistons: Part No. 9302039
• Mahle 604 Pistons: Part No. 9301278
• Total Seal 602 Piston Rings: Part No. CRG2010
• Total Seal 604 Piston Rings: Part No. CR6264

No other aftermarket pistons or piston rings are approved unless specifically authorized by IMCA. All repairs must otherwise conform to the Factory Circle Track Crate Engine Technical Manual and the current IMCA 602/604 Crate Engine Repair Guide.

All repairs must utilize approved GM Performance Parts, with pistons and piston rings remaining among the approved repair exceptions outlined by IMCA.

Any engine requiring this repair must receive the designated IMCA major repair cable seal package, including the required red "BORED" identification seal and five sequential black seals. All repair documentation must be submitted to MCA before the engine is returned to competition.

"This amendment provides a cost-effective option when repairing a crate engine while continuing to preserve the consistency our racers expect," said IMCA President Brett Root. "By allowing approved overbore repairs with specific MAHLE pistons through our Authorized Repair Center network, we can extend the service life of these engines without compromising the integrity of the IMCA crate engine program."

Questions regarding the amended crate engine repair rules should be directed to IMCA Competition Director Dave Brenn at 785-307-8482 or IMCA at 319-472-2201.

For more information, visit imca.com.