Ugh, hadn't bothered to read this thread.
Everyone who thinks the AMC 4.0 is all that - f' off. Yeah, it's a great truck/wheeling engine for it's low end grunt and realiability. It is NOT a performance engine and NEVER will be. I think Dino's numbers are out-to-lunch, based on my own experience in the area. He did a lot of guessing, and buying into advertisment BS. Oh, and a 4.0 weighs as much as a BBC!
A Chevy V8 is THE cheapest engine to get power out of. That crate engine is dyno gaurenteed (IIRC) and for a good reason. Not to mention it has a factory warranty. Also, as is the nature of USEABLE power, the torque curve (and HP) curve of the chevy engine will be far more usable for a street application.
Also, it's generally better (in the long run) to not be trying to get an insane amount of power out of an engine for its size. It's a longevity thing.
Anyways, S-10 eater, looks damn nice! If I was building a street truck I know it'd be powered by something like that. And carbs are great for street applications - but they blow off-road.