Quote:
Originally Posted by Jimbobeast
I beg to differ. The aftermarket springs were installed without machining the valve stem "boss". The inner spring sat 1/4" above the seat (and the outer spring), giving an effective seat pressure of 160. The springs were OK for the application but were installed incorrectly (and assembled by a previously very competent Pontiac loving machine shop).
The boss is now machined and the inner springs are flat on the seat along with the outers. All is in harmony.
|
A 322psi rate spring with a 110psi seat pressure will put you at 271psi open pressure at 0.50" which is perfect. I had a set of 670s done and used the 995 402psi spring and have 292psi open which is perfect. Not sure the focus on closed pressure but I would keep open pressure to 300psi or less.
Also, I would not trust anyone, Pontiac friendly or not, who did not verify a spring fits before installing. Not by a country mile. The issue should have been caught when checking the spring pressures before sending the heads out the door too. Two strikes right there. The third would be them willing to fix it for free. I'd run the other way with the heads you have. Scary really.