It should work, IF... you can take some measurements.. over all length etc... but a BOP TH350, should be a pretty direct swap.
Hey, if you get to that point and need a hand, let me know. If I can get away, I'll gladly give you a hand with it! (give me some lead time if possible as to when you plan the swap)
The seals should be easy once it's out and accessable (front and tail seals) The Torque converter... well? you may want to get a new one as you'll produce a little more torque in a different range than the stock V6... and that one may mount to the flywheel differently? I'd get a new one just to be safe. You can get one from Jegs/Summit pretty cheap...
Keep me posted!
Brett - 67 Drop Top 455! brettnheather@hotmail.com