Quote: the mp stage 6's have some fatal flaws, imho. the valves are too short, the valve spring pockets are too deep, and there were some qc issues early on. the short valves and deep spring pockets restrict the port shape going into the bowl (the roof of the port is low and can't be raised). there are plenty of eddies running nines, maybe even eights, prolly.
Those issues on the Stage 6's can be addressed , they were on the heads we ran on the EM470.
