[Arran]

I wasn't thinking of a Chebby 400 but a Chrylser/Dodge/MoPar 400, which is a B series big block like a 383 with larger bores. It's similar to a 440, which is an RB (raised block) engine. All of those have the distributor at the front on the right side, but the oil pan sump is at the back, so it may be less of an issue then lets say stuffing a Ford BB in there. The height of the hood may be an issue in terms of fitting a 440 in a Vette, but then again G.M put 396s and 454s in coke bottle Vettes, not sure what chassis and body modifications they made to do it though. Then again it would likely be smarter just to buy a Jensen interceptor and fix it up.
Regards
Arran