I have acquired a spoon 2 layer HG from a friend of mine in the quest for a little bit more compression. I had thought that it would be a good idea to get even more compression out of this setup (while using stock bottom end) by gettin my stock p72 (gsr) head milled. I was wondering if anyone knew the service limit on GSR heads when it comes to milling?? I am currently looking at gettin it milled .020 or .010... both offer a decent compression increase that i see worthwhile. Any recommendations, how far can i go without having to worry about hitting valves with the 2 layer (stock cams).?????

My actual GOAL for this would be a compression ratio of about 10.4 to 10.6.

 

sorry but why would u want you GSR to have 10.4- 10.6 comp? u wouldnt feel much of a diff

 

I dont have the money to go for an allout bottom end build , 10.6 compression over 10.0 would be a pretty good difference for the little money you spend on milling and this headgasket............. why not?

 

the JDM GSR (10.6) over the USDM GSR (10.0) isnt very much different. its unnoticeable.. u should mill your head to get at least 11.1 compression. i will raise my JDM GSR motor to 11.5 soon and run bigger cams g/l

 

If you obtain 11 to 1 compression by milling your head, it will probably result in valve to piston contact. I dont think anyone has milled that much off their head.