if you're looking to use what you have and spend as little as possible, as was already mentioned, 350 block 307 crank. get an adapter to run the two piece seal crank in the one piece block.
if the lifters seem to roll and collapse ok, i would say go ahead and try it.
using 305 heads is going to drive up the compression, and i don't think I've ever seen a dished 327 piston. that may be what stops the project from being cheap.