I can tell you the tensioners are different between the 5.7 and the 6.1

I believe the base circle on the cams are different also.

6.1s run a valve spring "shield" intended to control spring "squirm"

6.1s originally came with a "blue stripe" intake valve spring - this is allegedly a higher seat and open pressure than the "green stripe" you'll find in most later crate motors.

Probably not much help to you but there ya go.....