I am reading that gt40p's have a different height keeper groove on the exhaust side. i was wondering if its the same for the 3 bar heads and if so, how mch difference wold it make on a .512 lift cam if i didnt put a different retainer or keeper on the exhaust side? I already have the kit good for .550 lift and didnt know about this before i bought the kit from a friend of mine. the retainers and keepers are the same on both the exhaust and intake.