360 vs 383
For me, I think the decision between a 360 or 383 is too project dependent to say which way I would go in a theoretical thread like this.
I think the 383 has some real advantages over a 360. I think the available aftermarket BB heads are better and I like the shorter stroke and bigger bore, distributor location, external oil pump and dry intake. But the only reason I can think of to build one is if I really wanted a BB. And I would probably lean towards a 383 over any of the other BB's because I am sure it would be big enough for what I would want and wouldn't be cylinder head limited as much. Built right, it would rev like a big 340.
But most of the time I would probably just do the 360. I can find a 5.9 that probably still has cross hatching (good luck with a 383), run a roller cam relatively cheap, have the option for port EFI if I want to get "wild" and make all the power I need.
I like the smaller engines, in theory they can do enough and use less gas at the same time and I've never lusted after a 500 cid motor. Not that the idea doesn't sound cool, but I don't need it and I'd like to be able to road trip my car and not stop at every gas station along the way. Helps that I'm not competing or anything. Just has to be something I like and want to drive, so the only competition is internal.