Re: 350 to 454 conversion
Welcome to Team Camaro! There is a lot of info on this swap to be found searching the forums using such terms as "big block", "big block mounts", "big block springs", etc. We've helped two people with this swap in the last week, so you may even see threads just by looking at the last 10 days or so in this (engines) forum.
Do the search, and then if you still have questions, come back. My 69 is a former 6 cyl car, now with correctly mounted BB. Lots of us have done this swap.
69 'vert project big block/TKO 600 RR
68 'vert driver RS clone -- gone!