Thanks Alan. Yes, I have heard of shaving the heads. Old hot rodder trick that goes back to.... at least 1930's. I think they called it milling the heads, cuz was usually done in a machine shop. I find it very interesting that the teams wait until the last minute to assemble the engine, determined by gasket size. How many gasket thicknesses are there? Must be a bunch, to cope with conditions. Man this sport is soooo hi tech anymore. I have watched videos of T/F in late 90's, and sometimes they didn't even pull the heads. Dick LaHaie would tune by checking the bearings. They still ran high 4's in the 1/4 mile.....