On the other hand if you wanna not mess around and get the best bang for the buck.. you can still get motorhome 440's running for well under 1k.. only major expense putting that in would be headers.. with a cam/intake you would have a killer a-body..
True story, I just picked up a 440/727 complete from alternator to neutral safety switch switch for $500 and I already had a set of mounts to drop it into my 69 barracuda instead of the slant six... Money well spent