You could still do the long Ford rods in the 350. I just mention this because you can get them very cheap, and you have the machine shop to make the needed modifications. The dome pistons and hogged out open chambers would probably build a respectable engine. If it was me, I would just not build a run of the mill engine.....as you can see from my latest creation.
I like the 400 best of all, but I would hate to see it setting around as decoration.