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Valve Springs

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How they hell are you supposed to know which ones too run?! Here's a little back story and why it interests me at the moment.

Got my car dyno tuned last year with my H/C/I car, heads were out of the box trickflow 170s, 7-angle valve job, and anderson motorsports valve springs. The springs the previous owner said were good to .650 lift. Well I looked up the springs on the AFM site and it says that the open pressure is 590lbs. From what I've been reading online, the open pressure is the important number and on a moderate performance small block engine, the OSP (open spring pressure) should be around 360lbs. The cam that I'm running is the anderson ford motorsports N-412. I want to make everything is in perfect running order for when I go get my car retuned hopefully sometime in the near future!

Here's a link to "my" valve springs


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usually it will be on the Cam card as to what pressure ranges to run for springs. It can also usually be found on the manufactures web site. Too strong of a spring and you are wasting power to open them and can damage valves from them slamming closed. To soft a spring and you will get valve float at a lower RPM. Even when you buy valve springs with a given rating you need to check them as some may need to be shimmed to improve the tolerance across all of the springs so they are Equal.


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That's what I've been seeing. I never got a cam card as I bought my cam second hand. I've tried getting it from AFM directly before but have been pretty unsuccessful. I'll probably give them a call tomorrow to try to get the recommended spring pressure.

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Jason, how did you measure for what height spring or diameter you needed to run on your heads? I'm sure it's slightly different for a modular but I'd imagine the process is similar.

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Well i looked At max opening of .581 and cams is .580-1 in lift. Coil bind is 1.xx or so. Then i looked at seat pressure.

*Crower 62802-2 cams

*Manley steel or titanium spring -16 springs.

*manley titanium keepers with stock steel valve locks. Im still less then 11k miles on them.

On the dyno they do not float. Which is good and every springs has been verified to manleys specs before assembly.

Sent by smoke signals

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