Not sure why there would be a head gasket problem unless you went larger than a 4.50" bore, the O-rings would be pretty close together and not much block material left since KB has the 4.80" bore spacing. With most aftermarket wedge heads, you would need the larger bore to keep from shrouding the valves, not an issue with Hemi valve angles as they point toward center of bore. You would have to plug the oil drain backs on the KB block as the wedge head doesn't extend as far as the end of the block on the lower corners, and you would probably have to mill some drain-back holes in the block to dump oil from the head back into cam-lifter valley, not ideal as oil winds up draining directly on spinning crankshaft, but not much else you can do, unless head manufacturer has added some meat on the end of the heads for a drain-back that matches the Hemi block. Back in the early 70's, the Mopar teams in NASCAR, modified the Hemi blocks to run the 440 heads because they could run much larger restrictors than the Hemi's at the time, finished 1.2.3.4 and 6 out of the top 10 at the 1971 Firecracker 400 at Daytona, shortly after NASCAR slapped a much smaller restrictor on them, making the combination obsolete.
