From what I understand regarding a 350 small block engine is that you have to check the block numbers and make sure your getting one that is dated 1977 or older cause they have a higher nickel content.
With so many people responding to this post I am really suprised that nobody has mentioned it to you so far, otherwise your going to be getting that BAD GM Mexican 350 engine that is not near as good as the the older ones, for example the Mexican engines have a soft cam and it has a softer cast iron crankshaft and the engines wear out faster due to low nickel content.
And also make dame sure that the 350 you buy is not been bored more then .30 over or better still get one not bored out at all, check your numbers out and make sure you know what you are looking for before you go looking around, also with small black some heads are way better then others the newer heads are not as good on gas as the older double bump or otherwise called Dolly Parton heads.
I would say don't buy a crapy crate engine at Autozone or GM crate its not the best instead rebuild an older 350 core engine if you can't find a good running one, and a standard overdrive is probably more reliable then a 200 or 700R4 overdrive, a 342 gear ratio is your best bet.
One last thing put an add in the paper and look for one in the fall and winter I have better luck looking for parts at that time, untill then most people are so busy that they have no time to look at a paper. take care.
