It's so easy to bag on the tried and true GM small block 350. Tech lovers will chide it for the decades old architecture. They'll point to its pushrods as a vestige of another era now that we live in a world of overhead cams and variable valve timing. When it comes to bang for the buck though, critics don't have a leg to stand on. Because the design has been around for so long, tinkers and grease monkeys have had decades to squeeze amazing power from its eight cylinder block.
Parts are so plentiful that a good case can be made for the use of a 350 in your post-apocalyptic cruiser, simply because you could pull up to any smoking GM wreck and probably find a replacement water pump. And cheap too. Here's a brand new example found on eBay which puts out some strong power and only rings the 'buy it now' bell for $2,195. How can you go wrong?