if raising the intake roof be careful where the cut for the spring pocket is, not sure on your heads but most are very thin there, ask me how I know LOL
What is sufficient thickness to leave here?
I'm running the CompCams beehive springs, part# 26056, 400 lbs./in. rate, 1.100" Coil Bind Height, 160 lbs@1.800", 420 lbs@1.150". Can't imagine going to a much higher pressure than maybe 550-600 lbs in this street application.
I should be able to gauge the thickness with either my ultrasonic tester.