The 270 block can be bored .125-inch oversize to 292cid. A 302 head will require pistons of the 302-type. Since the standard 302 bore is 4.0 inches, pistons of the slightly smaller size may cost a little more.
There is currently a 270-H head advertised in the "Classifieds," but there was quite a bit of interest in that relatively rare item, and it may now be gone. Typically these heads are much more expensive than the 302 equivalent. The 270 crank and rods should fit in a 302 block with no problems, and boring the 302 .125 oversize yields 320cid.
i hope that you and your father will have the opportunity to enjoy that GMC-powered "hot rod." i know just how he feels. In the sixty-fifth year of my age, after hauling heavy pieces of cast iron around for many years, i'm almost up and running with a fine piece of machinery. We learn patience and continue to hope.
God's Peace to you.
d
Inliner #1450
