Another question if I were to go with a 360 would using the 318 crank be an inexpensive way to stroke it out being that the 340 and 318 cranks are the same?
Spending the extra cash on a 360 for the cubes and a higher ceiling on performance future is a great idea only if you have the money. The 318 crank or the 340/273 will not fit the 360's larger journals.
If you stick with the 318, I would seriously look into piston replacement and if your going to use what you have in the area of heads, fine, just cam it up well and ad a set of gear and a converter to match.
Idealy, the 340 heads are to large. A smaller valve 360 head would be better on the cheap. Ported 318 heads would be what your looking for.
