I am almost done with my gsr head, and its been off for about 3 months, through out the rebuild, what im wondeirng is, i want to have the mating surface of the head shaved for sealing reasons, but at the same time i want to raise compression, what would be a good amount to shave off, without taking any chances. thanks alot

 

depends on:

cams
pistons
valves

piston to valve clearance is the main issue

 

ITR cams, Factory valves, factory pistons

 

id say look for a thin HG instead of milling the head. that way you can go back to normal compression if you need to.