Can't give a spring recommendation with enough info -hotrod1968 wrote: ↑Wed Feb 03, 2021 7:41 pm Looking for some advice on valve springs for a sbc. Putting together a 11:1 iron vortec headed solid roller thing for a crazy street car, looking at a comp 12-773-8 solid roller with a 977-16 spring. An answer from comp on Summit’s site suggested this:
For street use, 120-140 lbs closed valve spring pressure and 300-350 lbs at max lift of the camshaft. Max closed pressure would be 165 lbs and 385 lbs at max lift
Cam has a 3200- 7000rpm range
254/260 @ .050”
.582/.588 lift
977-16 spring has the following specs
OD: 1.460
Max Lift: .700
Seat PSI: 160@1.850
Open PSI: 440@1.250
Coil Bind: 1.200
I have PAC 1243 springs taken from a set of AFR 1458 heads which I think are way too much:
1200 Series Dual Spring
1.55″ OD
.812″ ID
.700″ Max lift
550 lbs./in. Rate
1.053″ Coil Bind Height
This is probably a foolish question, but assuming I’m right about these being too nutty for my application, can I run without the inner spring? Is there a way to know what effect this would have on the spring pressure? Or is this just no good all over? I’m trying to do this on the cheap with as many collected parts on hand as I can. Poor mans racecar. Hence the ported to death vortecs..
What are the duration #'s @ .020"?
Steel valves?
Peak rpm?