“The crate engine also gives racers a way out of the claim rule. Eighty pecent of the engine claims in past have been by 20 percent of the racers. Guys don’t like having their engines claimed, and this gives them a way out of that.”

The Checkered Flag

With tracks and racers from coast to coast, the IMCA is stronger than ever. Attendance is up and the action is better than ever. Those who have been to an IMCA Modified race know how good they are, those who haven’t don’t know what they’re missing!

Those who have been to an IMCA Modified race know how good they are, those who haven’t don’t know what they’re missing!

IMCA Engine Rule

Engine Specifications: All cars utilizing a GM604 crate engine must clearly display on both front roof posts the word CRATE. Must be contrasting in color from body, minimum two inches tall. Markers not acceptable.

(A) Crate Engine: Must use unaltered sealed GM #88958604 crate engine with additional IMCA Cable-Lok system—no exceptions. Upon inspection, any different, altered or missing GM seal bolts or IMCA Cable-Loks will result in disqualification, loss of all IMCA points for the season, $1,000 fine and a one year suspension from all divisions with crate option. GM seal bolt exception is IMCA approved and issued Cable-Lok repair system. $250 fine for any crate engine not using required pushrods, valve springs or rocker arms. $250 fine for utilizing altered rev-limiter components. Any driver using crate engine cannot claim engine or have engine claimed. During same season, no driver is allowed to claim an engine after competing with a crate. If a driver switches to a crate after claiming an engine, the crate engine is then claimable.

(B) Claim Engine: Any American make steel engine block allowed. Aftermarket and OEM performance blocks allowed. Cast iron or aluminum intake manifolds only. Steel cylinder heads and oil pan only. Flat tappet cam/lifters and stud-mounted rocker arms only. Magnetic steel retainers only. No shaft, pedestal, or offset rocker arms, titanium engine components, stud girdles or mushroom lifters. Lifter diameter and configuration must match OEM passenger block. OEM firing order cannot be changed (GM: 1-8-4-3-6-5-7-2). All engines must be able to be used in conventional passenger car without alterations. Engine mounts cannot be removed or altered. Castings and fittings must not be changed. No machine work on outside of engine (no lightweight engine blocks). All belt driven accessories must be on front of engine. ‘Wet’ sump oiling system only. External oil pumps go with engine if claimed.

25. Engine Claiming Rules: Refer to www.imca.com for claim eligibility requirements.


$1,050 cash, or $100 and exchange, claim on engine, flywheel and balancing plates ($25 goes to wrecker and $25 to official for each engine). Claimed driver has option of accepting cash, or exchanging engines with claiming driver.


Claim does not include–1. clutch, 2. pressure plate, 3. bellhousing, 4. headers, 5. carburetor, 6. starter, 7. motor mounts, 8. oil/temp. sending units, 9. carburetor spacer, 10. fan and pulleys, 11. clutch ball, 12. clutch arm, 13. throw out bearing, 14. dip stick, 15. water pump, 16. fuel pump, rod and plate, 17. distributor, 18. plug wires, 19. water outlet and restrictor, 20. breathers.

With the ever-rising cost of race engines, coupled with the downturn in the economy, the IMCA made a bold move, allowing 604 crate engines in its premier series

“To many racer’s surprise, the crate engine has been very competetive”