Why do you say that? My dad has a '63 chevy ii. he just mounted new brackets for a 572 crate. There was no problem fitting the block with heads etc. The only thing that has to get changed is the battery moved to the trunk. But, trying to fit that with a 6L80 means that a new floor needs to be put in, that being a '73 Camaro, so the tranny has extra clearance for external computers and shit. Chevlles, being larger and having larger engine compartments/bays, would make it even simpler to fir the 572, let alone a smaller engine. need pics?