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Rocker Studs
Pontiac V8 Rocker Studs
Press-In To Screw-In — Rocker Studs for Pontiac V8s
Rocker studs carry every bit of spring load the cam puts into the valvetrain. Factory Pontiac V8 heads used pressed-in studs, and those are the first thing to let go when lift and spring pressure climb, which is why a screw-in 7/16 stud conversion is one of the most common upgrades done to a set of Pontiac heads.
Butler stocks ARP 180,000 psi 7/16 studs, Comp Cams 7/16 studs with a guide plate locator shank, PEP grade 8 kits, Speedmaster press-in conversion studs with a 1/2" base for 389 and 421 heads, and Butler's own 7/16 stud upgrade kits for 1961-1966 389-421 heads and for 1967-and-later heads.
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1. What You Have Now Decides What You Buy
Two jobs land here: replacing screw-in studs, and converting a head that still has pressed-in studs.
| Replacing screw-in studs | ARP offers a 7/16-14 by 7/16-20 stud at a 1.750" installed height, rated 180,000 psi, and a 7/16 by 1/2 kit at 2.000". Comp's 7/16 stud has a 1.900" effective length and a guide plate locator shank. PEP's grade 8 kit is a 7/16 stud at 1.750", using 7/16 rocker balls and lock nuts. |
| Converting from press-in | ARP recommends heli-coiling and using the 1.750" stud, because of its reduced hex thickness. The 2" kit may require cutting the studs to length. |
| Butler kits by year | Butler's 7/16 stud upgrade and conversion kits come for 1961-1966 389-421 heads and for 1967-and-later heads, in lock nut and poly lock versions. The poly lock versions include machined washers so the lock does not bottom out. |
2. The Machine Work Is Not Optional
This is where a stud conversion goes wrong, and Butler's product notes are blunt about it.
| Drill and heli-coil | converting press-in studs means the holes must be drilled and heli-coils inserted for 7/16 threaded studs. |
| Mill the bosses on early heads | on 1961-1966 389-421 heads the stud bosses must be milled, and Butler says that work should be done by a qualified machine shop. That is why the early-head kit ships with the thinner-hex ARP stud. |
| The 1/2" base alternative | a conversion stud with a 1/2" coarse base and 7/16 fine on top, .75" coarse thread, 1.00" fine depth and 2.25" overall, replaces press-in studs on 389 and 421 heads and lets factory valve covers fit. Have a shop tap the heads; hand tapping will not give a straight stud. |
| No generic torque spec | every casting is different. Pre-1964 heads have little material left once the studs are out, and they crack easily. |
3. Early Heads And Through-Stud Oiling
Certain pre-1964 heads oiled the rockers through the stud, and replacement studs have no oil-through holes.
| What to run | on oil-through stud applications, use rocker arms and pushrods that have an oil hole. |
| Keeping oil out | Butler also plugs the block with two 1/8 NPT pipe plugs at the deck to keep oil away from the heads, though that may not be mandatory. |
| Order the rest together | 7/16 studs want 7/16 lock nuts or poly locks and, on most performance valvetrains, guide plates. |
Bring us the casting numbers and tell us whether the studs are pressed or screwed in. The right kit depends on which head is on the bench, not on what the engine is called.
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.