An L-72 will have 4 bolt main bearing caps and an L-36 will have 2. Look above the oil filter and see what predrilled oil fitting holes are there. An L-72 will have a 3/4" and a 1/2" tapped holes, an L-36 will have just a 1/2" oil fitting hole. If the car is original, An L-72 will have a SINGLE 3/8" fuel line and an L-36 will have both a 3/8" and a 1/4" return line. The same engine was used in both Corvette and full size, and you need to have the front pad stamping to know what trans it came with. Don S