Welcome to the IMSA History unofficial website

This site is aimed at bringing you memories from the glory days of sportscar racing in the US.



Tico Almeida and René Rodriguez ran the ex-JLP Chevrolet Corvette at Sebring 1980.

The AAGT were specially American built prepared race cars. It was created by John Bishop in order to counteract the German cars domination. They were allowed a wide range of modifications.

Proprietary engine block must be used. Displacement may be changed by boring, sleeving or stroking.

Cylinder heads are free except that method of cooling must remain as original.

Induction is free, except supercharging is only permitted on engines under 6.0L.

Turbocharged engine displacement is 1.4 X actual displacement.

Rearmost part of engine block must lie ahead of windshield base. Firewall may be relocated to achieve list.

Drive Train:

Gearbox or transaxle are free except that there can be no more than 5 forward speeds.


Free. Standard wheelbase must be retained.

Brakes, suspension and steering are free. May have completely tube-frame constructed chassis.


The outside surfaces shape and material of the original coachwork must be retained and must remain identical, except for the additions, modifications and substitutions permitted in these rules. Overall length of the coachwork is regulated by the FIA recognition form. Maximum overall width is 83".

Material of engine and luggage compartment covers, doors and fenders is free provided their original shape is retained. Doors must remain functional. Front engine cars may add an air scoop to accommodate the induction system (maximum height above standard hood is 5.5"). Fenders are free in shape and material but are limited as follows: Original wheel arch must be retained and must effectively cover the full width of wheel and tire for 1/3 of their circumference; any rearward opening must be closed by screens or louvers. Bumpers and external decorative trim may be removed; door sills may extend to the full width of the bodywork. Any additional bodywork must not confuse the make and model identity of the car.

Wheels and Tires:

Wheel and tire section width (maximum width at widest point of tire) may not exceed: Under 6.0L - 20" Over 6.0L - free; diameter free.

Track dimension is limited by inner tire clearance and the permitted maximum car width.

Aerodynamic devices:

Front spoiler may not exceed 10% of the wheelbase or protrude a maximum of 20cm (7.87") beyond the front extremity of the coachwork, and must be located below the centerline of the front wheels.

Rear spoiler chord may not exceed 20% of the wheelbase or extend beyond the rearmost bodywork more than 40cm (15.75").

Specifically allowed:

Crank-fire ignition Polycarbonate windscreen and windows Quick-change rear axle Items allowed under FIA Group 5 regulations when contrary to the above are permitted on documented FIA Group 5 cars.