How much variance is acceptable between installed heights? Just pulled springs off of a set of heads to take the inner springs out for cam break in. While doing this I ck'd installed heights and have over .020 between valves. Aluminum heads and they used a spring seat that locates on the boss, shims under the seat and you can't remove the seat without removing the seals. Is this the best way for this setup? Springs are 978-16 Comp for a solid FT cam. Springs recommend 1.850 height, cam is under .600 lift.