bottom end. AMC never built a factory four-bolt main block, they sold aftermarket four-bolt main caps through their Group 19 performance parts program. The SR block was also sold as a heavy-duty racing block. It appeared in 1970 in time for the 1971 Trans-Am racing season and was used in the factory Trans-Am backed cars prepared by TRACO for Penske Racing, with Mark Donohue the primary driver. Since it was a standard factory part it did not have to be homologated under T/A rules, and was not used in the 2501 "Mark Donohue" Javelins built to homologate the "ducktail" spoiler. Those received standard 360 or 390 engines, buyers' choice. Engine specs Note: Prior to 1972 figures are rated using SAE gross. Later engines use the current SAE net rating. Indy 209 From 1976 until 1979, Jerry Grant "drove the most powerful car ever to appear in Indy car racing" - a turbocharged two-valve, AMC Gen-2 block V8 engine producing in his Eagle 74 chassis. The car was fast on the straightways, but the engine's weight made corners more difficult to handle. The engine utilized a bore and a flat plane stroke crankshaft. See also AMC Straight-4 engine AMC Straight-6 engine AMC/Jeep Transmissions List of Chrysler engines List of AMC Transmission Applications References Inline General V8 V8 V8 V8 engines