Originally Posted by
inferno13
you awnersed your own question
, try all 4 and let us know what you come up with....LOL
use one copper shim. The head button has a clearance of .27 if I remember correctly.
alternatively, you can go to 40% nitro and use all three shims. The increase in nitro more than compensates for loss in Oxygen content and ambient air pressure. If you're still having trouble, performance-wise, remove one copper and add an aluminum shim (2 alum, 1 copper).