Block's the same between 273, 318, and 340 with exception of bore. Running a 4" crank or the 3.58" 360 crank in a 273 will be just like running it in a 340 except for the pistons. Nothing special below the pistons.
Pretty much about the 360 heads. You're typically talking about 68cc+ chambers compared to 62cc+ chambers, then with thicker head gaskets common- down in the low 8s with stock 2bbl pistons. I'd be curious how easily you could get away with stock pistons in a stroker with the makings of big compression drops that are not uncommon.
