well im into buliding my 360 now and i need some info on the heads. will post cast # tomorrow. think there 596 . anyways, i need too know when is it time too reguid them. theses have no inserts, but valves seem a little sloppy in the bores , will i need a dile indicator too measure them> waht is the allowable clearances? the faces and seats look good. and whats with this big hump in the exhaust runner? can i mill it out?going too be swithing too flat face valves and milling 20 too 30 of the heads soon .