Slant Six head swap?

I'd have to look, but I thought the plugs pointed the same on both the 'peanut' heads and the 'drool tube' heads. And, I agree, you will see little (if any) compression difference. Most stock slant heads are in the 55 +/- 5 cc range, early or late heads, so swapping heads would be a crap shoot for little, if any gain. The only practical way to increase compression is new pistons or head shave/block decking. You better do the math to make sure you get what you want.
jus sayin....