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Stock Cast Iron Heads
Pontiac V8 Stock Cast Iron Heads
Working Inside The Pocket — Stock Cast Iron Heads for Pontiac V8s
Valve springs for stock Pontiac cast iron heads are a packaging problem as much as a load problem. These castings work around a 1.600" installed height with a spring pocket that was never meant for a modern roller cam, so the spring has to make the pressure without going coil bind or requiring machine work you did not plan on.
Butler stocks flat tappet and hydraulic roller duals from Comp Cams, Crower and Howards, plus complete Butler spring kits that add Comp retainers, Comp locks, Viton valve stem seals with the install tool and an assortment of shims. Light checking springs are here too.
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More About Stock Cast Iron Heads
1. Why Cast Iron Heads Get Their Own Spring List
Everything on this page is sized for the installed height and pocket a factory Pontiac casting gives you.
| The working height | these springs are specified at 1.600" installed, not the 1.800" that the aluminum and Ram Air IV heads use. A spring built for an Edelbrock head will not land on the right pressure in a cast iron head. |
| Pocket diameter | outer diameters here run in the 1.384" to 1.465" range. That is what fits without opening up the seat area. |
| Machine work warning | Butler notes on the Comp dual hydraulic roller spring that cutting valve seats may be required in a stock cast iron head. Know that before the heads leave the shop, not after. |
2. Flat Tappet Or Hydraulic Roller
The cam you are running sets the pressure you need, and the two paths split cleanly.
| Flat tappet, mild | the Comp Cams 1.384" dual is 117 lbs at 1.600" and 240 lbs at 1.100" with coil bind at 1.000". That is a stock-rebuild and mild-cam spring. |
| Flat tappet, more lift | the Crower dual runs 113 lbs at a 1.600" installed height, 284 lbs at 1.100" and 304 lbs at 1.050", with .950" coil bind and a 1.405" OD. Butler notes it can be used up to .590" lift on cast iron Pontiac heads without cutting the spring seats, which is the single most useful fact on this page. |
| Hydraulic roller | the Comp dual is 155 lbs at 1.600" and 355 lbs at 1.050" at .550" lift. Butler's Howards dual is a dual-with-damper at 145 lbs at 1.600" and 370 lbs at 1.050" at .551" lift, with a 1.465" outer OD, 1.091" outer ID, .807" inner ID and .950" coil bind. Butler's own dual runs 140 psi at 1.600", 350 at .500" lift and 375 at .550" lift. |
| Running a roller spring on a flat tappet | Butler lists a recommended installed height of 1.700" for 115 lbs when the Comp dual hydraulic roller spring is used with a hydraulic flat tappet cam. |
3. Advertised Coil Bind Versus Measured
This is the number that bites people, and Butler publishes both.
| The discrepancy | on the Comp dual hydraulic roller spring the advertised coil bind height is 1.020", but the actual coil bind measured with the matching retainer is .980". Design to the measured number. |
| Why it matters | a spring that stacks solid before the valve reaches full lift breaks parts. You want clearance between full-lift height and coil bind, not a coincidence. |
| Check with your own retainer | the retainer changes where the spring stacks. Measure the assembly you are actually going to run. |
4. Springs Alone Or A Butler Spring Kit
| Kit contents | Butler spring kits for cast iron heads come with the springs, Comp retainers, Comp locks, Viton valve stem seals with the install tool, and an assortment of shims. Butler offers them built around the Comp hydraulic roller dual, the Crower flat tappet dual and Butler's own hydraulic roller dual. |
| Why the shims are in there | installed height varies head to head and after a valve job. Shims are how you land on the seat pressure the cam card asks for. |
| Checking springs first | light checking springs let you cycle the valvetrain by hand and confirm geometry, retainer-to-seal clearance and pushrod length before the real springs go in. |
Measure your installed height on the assembled head, then bring that number and your cam card to the counter. The spring that works in your neighbor's 400 may land on a different pressure in yours after a valve job.
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.