Superformance rollers can be ordered with small and big block Ford engine mount setups, FE's, 385 series etc, and Superformance has headers for their cars and these engines setup ready to go. Changing to something like an LS2 would mean different (custom) mounts, new custom headers, a ton of minor mods as well - fuel systems, engine management systems, wiring harness adaptations etc. Superformance rollers are complete - body fixed to frame, painted etc - so it's not like a kit where you don't put the body on until the frame has been adapted to your build plan. I would recommend not doing this, but obviously, it could be done probably with enough time and money
Then there is that Chebby factor
