I ran P heads on mine for a few years. No need to shave the shock towers, although I did shave mine a couple years ago 'cause it does make it a lot easier changing plugs. With the P heads I ran my old Blackjack headers. Had to notch the header flanges a little to clear the plugs, used shorty Accel plugs on one side (driver's?), used shorter distributor terminals and boots on the spark plugs and had a modified spark plug socket to get in there. If you do a search on here there's a lot of info about using P heads. The non-P Gt40s do make life a lot simpler.
Well seems easier to swap he gt40 non p's onto the roller motor and just transfer over my roller rockers. Do 1.72 roller rockers clear on a stock roller with gt40 heads? They clear my current setup so don't see why they shouldn't. Machine shop told me 40 bucks to clean my non p's and swap over springs and retainers from the p heads setup for the roller. busy busy busy.
you shouldnt have any problems with the 1.72 rockers. when you have the heads off make sure you have valve reliefs in the pistons. its also just good practice to check the piston to valve clearance. its easy. save an old head gasket. put some clay, playdough or even a tootsie roll in its rapper works well on the valve reliefes. put the head on with just the 4 head bolts around cylinder number just tightened down snug. put in the push rods and rocker arms and rotate the crank twice and take it all apart.
