So I picked up a 360 short block and and an extra crank today... free. Looks to be a 77 out of a truck. No idea what I shall do with them, but one idea is to stuff the 360 crank into that poly build down the road.
The main journals on the 360 are larger than the 273/318/340, I'm not sure that you can just drop it in a 318 and go without machining the crank bores in the block and caps for the larger diameter main bearing journals of the 360....
they also made the thrust bearing flange larger on the 360 in mid 74 and you may also have to have that machined to match also...