I'm keeping her pretty much stock, and while I am not in the fiant of heart category, the military dont pay so much that I cant say I dont fall into the faint of wallet one.
I was looking on a website for one piston company that makes stock re-pops of all sorts of engines. I didn't see any 270's, but there was a load of 292 & 302. I'm gonna get one of the pistons form my engine & do some measuring on it to get exact pin heights, pin thickness, all that fun stuff, and bounce it off them. I'm relatively certain I can find another piston from some other engine that will work fine in the 270 bored over to 3-13/16".
Of course, all this will be in the air till I can get the block in to be magna-fluxed before I bore it, gotta make sure it's a solid block. Gonna do that shortly, just wanted to see what sort of bore I was looking for 1st.