Without changing anything? Another 273 2bbl. Minor mods.... most 318 long blocks before '75 will swap right in if you use your 273 parts, you'll just need a crank bushing for your '64 904 trans converter, or a later Magnum pilot bearing for a manual trans. A 340 would require engine mount mods, and major exhaust work to make it work properly with the 340 heads. With a 360, you need the same mods as the 340 along with" a 360 car oil pan that will fit the '62-6 K-member, remark the 360 balancer for the passenger side timing indicator or you will have a hard time seeing the driver's side one to set the timing, conversion flex plate or weighed converter, or, a custom balanced flywheel for a stock manual trans setup. If you go with a 4bbl on any of the swaps involving an auto trans, you'll also need to get a 4bbl kickdown assembly, or, a Lokar cable kit to convert from a 2bbl. A 4bbl air cleaner too.
