Has anybody seen different valve height in stock heads? I've got 2 stock heads. One from a G20 and one from a SE-R. The Se-r motor was in my race car with S5 cams and ran great till it tossed a rod at Buttonwillow. I got a motor to rebuild from a G20 and as I was assembling it I found that the springs are binding just before max lift on the cam. It seems to be .030 from being able to open fully. I don't know what the difference is but the assembled height is .030 less than that of my old motor. I have pulled my old head and am rebuilding it cause the cams work in it but I don't know what to think about the G20 head. It's now rebuilt but I can't use it with my cams. What am I doing wrong here? I'm new here and maybe missing the obvious so......

have you consulted an FSM at all? Going off the top of my head I think there is like 2 different positions you can set the valve stem tip height when installing the retainers and keys...I could be wrong, but I remember something of that nature.
An FSM should spell it out clearly.