got the cams, springs, retainers and springs. I wanna drop them in but someone told me that I should mill the head to raise the compression. Is this right. if so how much should it be milled. I do not want to have valve piston contact that would be really bad. Oh yeah this is all for a 2000 Civic Si B16a2, stock bottom end.

 

Just milling the head won't give you the compression you need to run those bigger cams. Instead, why don't you wait until you get some pistons to put them in. You're going to need a higher compression to support the cams, I think some CTR pistons will do the trick on the b16a. You have to consider the entire engine package. Once you put those cams on, you will be overcamming your engine hard and you'd be better off with the stock cams. It won't be until you raise your compression enough. Research Dynamic Compression, should give you more insight on why I say this. Hope it helps, if not, ask away.