I find many springs to be 10-15lbs off.
Example...
Comp 995..
Inst. @1.65 chart shows 135lbs..and @1.150 shows 335/340 ...but is actually more like [email protected] and [email protected]
1.72 125lbs , 1.220 335lbs.
I find that to be true pretty often for many new-in-box springs.
They’ll often fall back closer to “spec” after several high rpm blasts.
But not always.
I’ve had the heads come in for freshening after a couple of seasons and the springs still test higher than spec.
My experience is the old H11 drag race springs would lose a bunch of load in short order.
You really had to be sure to crunch them to coil bind several times before doing any testing.
I’d seen them lose 40lbs doing just that.
Then another 20lbs could easily be lost in a pretty short time if you were running a valvetrain combo that got into some unhappiness.
I’ve removed many dead K-950’s from bracket race heads, that should have been a pretty good match for the combo...... on paper....... but were obviously not up to the task.
