"Any company can sell poor springs at any time. No one in the commercial market makes springs, they are outsourced except some of the high end houses. The spring wire is generally made in Sweden or Japan and it too has bad batches. Harvey Crane said to me, if you find some good springs, buy all you can because the next batch may be inferior.
We run these springs far above the Spring Manufacturers Association's recommendations of 65% stress at around 90-95%.
So if it's not Comp today it's Crower tomorrow.
Good springs are also double to triple of the price Comp or Crower sell at."
From a PAC spring user.....
Quote:
Originally Posted by
aleborjas 
just get PAC #1533 springs and they fit with stock retainers
"We had a spring fail on my brothers livernois heads about 1.5 years back. Now I don't know who there supplier was at the time, but I believe I was told its PAC now. Anyways that spring broke, valve fell and took out my brothers 450km used boss block, piston and chamber on the head. So you got pretty lucky if nothing is damaged Steve.
His cams have the same duration as yours, but 0.495" lift.
We never did hear back as to what caused the spring to break when they ran a failure analysis.
I have Manley Nextek valve springs on my heads Steve. No experience with them yet, just about 45 min of run time before my secondary tensioner bed **** on me.
Last edited by torchred04; 12-01-2011 at 05:53 PM. "
Good thread here:
http://www.modularfords.com/threads...ng-QC-Problems?highlight=broken+valve+springs
