[Jesse Knapp]

I used Comp springs and their cam as well. They were 1.650 diameter. I did use the long stem valves and don't remember the installed height, but I do remember seat pressures were 350 to 360. Also, after a few passes they would "set in" a few lbs less. They would stay there for maybe forty or so passes. By then pressure would drop to around 300, but in my case this was all the valves. I would then shim them up to around 340 and go on racing. When they went down to 270/280 or so, they came out. I usually went the yr. on one set. My point to you is.......if, after 30 passes your pressures vary that far apart, either you are taking your readings wrong or you have some bad springs. And you can get a bad one from anybody. As I said, after a few passes, I checked them and they all dropped a bit, but not much. I would say about 340 from 350 or so. If I had one drop to 280 or so I'd take it out. Bad spring. I'd be willing to bet you are not comfortable with the LSM tool yet. I did have Manleys on my heads when I first bought them, and they were 1.6250 springs. Didn't work with them much. I sent the heads to Layer and went with Comp cams and springs. Recheck your springs pulling with both arms making sure, as much as possible, you do not pull slightly right or left. Believe me, you will do that in such a minor way that it's hardly detectable and it will mess with the readings. Humans are just not that exact. Hope this helps you.