305/350 swap

Well I know I already screwed my 305 over pretty good so I talked to a guy that my stepdad knows and his son has a 350 that they pulled out of a '56 Bel Air. They're not sure what year the engine is, all they could tell me was that it is from the 70s. If I get it as a long block what could I take, if anything, from my 88 305 to finish the engine?
I already know that I have to take my cam, lifters, pushrods, timing chain & gears from the 88 (they're aftermarket said to work for 56-94 Chevy SB 305-400 I believe). I know that if I were to put 305 heads on the 350 I would get great compression. But I know that with a change in the years I'll have a big change in emissions controls built into the engine. I would like to get all aftermarket parts to reduce the number of emission controls that the car has so that I can have a running car. Instead of fiddling around with it trying to get all the systems to work together. Any help would be greatly appreciated.

I have a L98 350 corvette engine from '88 in my caprice. It drives like a rocket!!! When I bought the car it was already in there so I can't be specific about any encountered problems, I can just tell you that it fits and it's a very fast car. If you like to see pics of the engine in my caprice look at the internet adress at the bottom of this message. Good luck.

Hey man. I know where your at since I have an 86 with a mild 355. I had a 305. I know u can use all the sheet tin and should be most of the parts (water pump, alt, brackets etc.) Your 305 heads are centerbolt 58cc. They will fit on an early block and will raise compression. Be sure to check piston to valve clearance. You may need diff pistons to run those heads. If u do use the heads u can use the intake and thus retain the stock emission components, BUT your computer will need to be recalibrated as the fuel curve will be wrong. I know this is alot to digest.
Personally, I would just go with the 350 long block and find a 4- barrel intake manifold with the EGR valve. Sorry man I could go on forever. Hope this helps some.