1991 S10 small block/big block swap

I am getting a 91 S10 from a buddy of mine for pretty cheap, and i wanna do a lot of work to it.  im thinking about swapping it with a chevy small block, probably 350.  i was thinking about just going all out and doing a big block, but i know the cost of building up one of those will be more costly.  this is going to be a project over the next year or so.  im not looking to spend tons and tons of money on it, but im very willing to spend money on what is needed - its not going to be a strictly track truck or anything.  im looking for some nice power tho, mayb 400-500hp.  what does anybody suggest?  working over a 350? or something bigger?  

i know plenty of other stuff is needed..trans, driveshaft, rear axel..im just focusing on the motor for now.  thanks guys.  

I would say that a "350" in a s-10 has been done alot. So if it were me I would opped for a "4 bolt mian 400". If you bore it 0.030 over you will make a 406 then I would put Dart top end on it with Accel Multi-port fuel injection. But make sure all the internals are forged because you only want to build it once!!! As for the Trans I would say a turbo 400 with ether a Trans Brake or a Good stall converter.
Keep a steel driveshaft if you can as for the rear axel a 9 inch is your best bet
but if not you can go for a 8.8 that are found in Ford Explorer's your still going to have to beef it up.  

400-500 hp might be a little crazy for a daily driver if you plan on saving some cash for gas and shoes for the rear rims.  i'd personally build a nice 350hp 350.  more than enough for a s10 and less hassle in the long run.  that being said it would be really sick if you had a 500hp s10 with a throaty v8 under the hood!  
-Cody

I would not recommend a big block for an S-10. Not that it couldn't be done, but that there is so much power potential for a small-block, that I think you're better off going that route. Honestly, unless you're aiming up into the 800-1,000 horsepower range, you can easily get up to 500 horse out of a small block. Plus, the small block is quite a bit lighter than a BB, so it would probably require less suspension & chassis mods to put it in there.

I think you could get good drivability and great power from a supercharged 350. I'd go fuel-injected if you could. A lot better cold-start performance and all-around drivability. The electronics can be a little bit of a headache, but there are enough systems out there, you should be able to find one that works.

If you can find one for a decent price, an LS1 or LS2 would be your best bet. They're super-compact and super-lightweight, and will give you close to 400 hp right out-of-the-box. Plus, they're pretty fuel-efficient. There would be some electronics work involved, though, since they're OBD-II engines. Just my $0.02.