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Valve Springs- Custom Install Heights and Pressures
Pontiac V8 Valve Springs- Custom Install Heights and Pressures
Shop by the Numbers — Valve Springs- Custom Install Heights and Pressures for Pontiac V8s
Valve springs listed by custom install height and pressure is where you shop when the spring has to match a number, not a head casting. Every spring in this category is described the way an engine builder reads one: outside diameter, seat pressure at a stated install height, open pressure at a stated open height, and the coil bind figure that limits your lift.
Butler stocks Comp Cams dual springs in chromoly, Pacaloy and H-11, and PAC 1.550" and 1.625" dual race springs, covering seat pressures from a 140 lb hydraulic roller spring up to a 353 lb solid roller spring, in outside diameters from 1.430" to 1.645".
Browse Valve Springs- Custom Install Heights and Pressures Products
More About Valve Springs- Custom Install Heights and Pressures
1. Why This Category Exists
Most spring listings are organized by head. This one is organized by spec, because that is what a cam card gives you.
| The cam sets the spring | a cam card lists a required seat pressure, open pressure and maximum lift. Those three numbers, plus your measured install height, pick the spring. |
| Head-specific pages exist too | if you want a spring already matched to a stock cast iron head or to Edelbrock, Ram Air IV and Super Duty heads, Butler has separate categories for those. Come here when your install height is not stock. |
| All duals | every spring in this category is a dual spring, which is what a performance flat tappet or roller cam needs to control the valve. |
2. How to Read the Spec Line
Each listing reads the same way. Once you know the format you can compare twenty springs in a minute.
| Outside diameter first | 1.442", 1.550", 1.554", 1.570", 1.625" or 1.645". This has to fit your spring pocket and your retainer. |
| Seat pressure at install height | a Comp hydraulic roller dual is 140 lbs at 1.750". A Comp Pacaloy solid roller spring is 236 lbs at 2.000". A PAC 1.550" dual race spring is 240 lbs at 1.900". That second number is the height you must actually build to. |
| Open pressure at open height | the same Comp hydraulic roller spring is 355 lbs at 1.200". A Comp 1.625" H-11 spring is 816 lbs at 1.150". Open pressure is what loads the lifter, the pushrod and the rocker. |
| Coil bind | listed as a height. Coil bind on these ranges from 0.900" up to about 1.160". Your maximum valve lift plus a safety margin has to fit between install height and coil bind. |
3. Match the Spring to the Cam Type
Butler labels several of these springs by the lifter family they were chosen for.
| Hydraulic roller | the Comp 1.442" dual at 140 lbs on the seat and 355 lbs open is listed for hydraulic roller use up to .580" lift, with actual coil bind measured at 1.100". Too much spring on a hydraulic lifter will collapse it. |
| Flat tappet | the Comp 1.625" H-11 spring at 250 lbs on the seat and 724 lbs open is the flat tappet listing. A flat tappet lobe has a finite amount of pressure it can survive at break-in. |
| Solid roller | the Comp 1.550" Pacaloy at 240 lbs on the seat and the 1.645" Pacaloy at 236 lbs at 2.000" are the solid roller listings. PAC's 1.625" drag race spring is built around a 2.000" install height and a recommended lift of .850". |
| Material | chromoly, Pacaloy and H-11 all appear here. H-11 and Pacaloy are the high-pressure materials, and they are what shows up in the 700 and 800 lb open pressure listings. |
4. Install Height Is Something You Set
The spring only makes its rated pressure at the height it is installed at. On a Pontiac you have three ways to control that.
| Shims | hardened spring shims in .015", .030" and .060" raise the seat and shorten install height, which raises seat pressure. Butler cuts them separately for cast iron and Edelbrock heads. |
| Retainers | a plus .050 retainer raises the top of the spring and lengthens install height, dropping seat pressure. The retainer also has to match the spring outside diameter. |
| Machine work | cutting the spring pockets is the permanent answer when shims and retainers cannot get you there, and it is also what you need if the outside diameter is growing. |
| Measure with the real parts | check install height with the valve, retainer and locks that are going in the engine. A number off a different set of parts is not your number. |
Send us the cam card and your measured install height and we will pick the spring, the shim stack and the retainer together rather than one at a time.
Not sure what your Pontiac needs?
Call our tech team at 866-762-7527. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.