I was wondering, what generally are the lift and pressure on stock springs

or

Is there an easy way to check them, is there a part number, a tool, anything. This would be ebtter for me to check if the head was on the engine still, but I could take it off if I must. Thanks.

 

If you are thinking about using them, think otherwise. Factory SBC springs belong in the trash. They are garbage. Rated at about 85 lbs of seat or so and a 1.710" installed, they are generally good for about .470" or so lift. They are garbage pieces at best. The best part is, factory springs can vary. After a few good cylces, the pressures drop, making them even worse. I've seen factory springs get Rimac'd down in the high 50's on seat pressure.

A Rimac is what tests spring pressures. Don't bother Rimacing factory springs. They aren't worth it. They are crapola pieces.

 

Basically agreed. Stock springs I have taken off MANY factory heads only provide about 65 lbs. seat pressure @ 1.70" installed height (which is the stock installed height of almost all modern factory SBC heads). Any kind of performance cam will overpower them.

They will take about .510" lift at that installed height but they only give about 220 lbs pressure at that much lift. Generally, not enough. Most stock heads experience retainer-to-guide contact at only about .470" lift. Many beleive the springs are the limiting factor, but they are not. The springs are good for over .500" lift before they bind. HOWEVER, THIS DOES NOT MEAN THEY ARE SUITABLE FOR PERFORMANCE APPLICATIONS!!! They belong in the trash can. Nowhere near enough pressure for a performance cam. Valve float can happen at frighteningly low RPMs.

If you want a good mild-performance valve spring that will drop right into a stock head, without machining, and give much more performance-oriented spring pressures, look at something like the Comp Cams #98848 springs. 105# on the seat, 265# open pressure @ .500" lift. It still won't help if you have limited retainer-to-guide clearance, but the spring itself will work well with most performance street cams up to about .500" lift.

 

Actually, I have found that they CAN be useful. After installing a twin-belt sheave set on my table saw, I used an old 80# valve spring placed in the motor cradle to help maintain belt tension. Worked GREAT! And spares are very abundant.

As for using them in an engine, on valves, look elsewhere for springs.

 

Well, Chevy does make a few good springs for a perf. cam. Try #3927142 or #10134358 (orange). They have 110# @ 1.70" and around 290# at 1.220". They coil bind at 1.150".

Auggie