[70K5AK]

Hey guys! I'm swapping a tired 350 out for a 396, in addition to swapping the TH350 with a TH400, all with NP205 T-cases. I got a new-to-me TH400 with a 205 already mated. From what I have researched and measured (based on my previous TH350/NP205 adapter setup vs my new TH400/NP205 setup), I'm going to add about 3" of drivetrain length due to the trans swap.

I'd like to leave my T-Case in the stock position so I don't have to cut driveshafts, move shifter hole, etc and just move the engine crossmember forward the approximate 3". I don't want to do a body lift. Do you think that would get me the adequate clearance from the firewall? Also, has anyone gotten away with this running stock-ish big block manifolds vs headers without notching the frame? Any other gotchas? Thanks a lot, great thread! Dave