- Home »
- Catalog »
- Valvetrain Components »
- Valve Guides and Seats
Valve Guides and Seats
Pontiac V8 Valve Guides and Seats
What The Valve Runs Against — Valve Guides and Seats for Pontiac V8s
Valve guides and seats are what the valve actually runs against, and they are the parts that determine whether a valve job lasts. A worn guide lets the valve wander and eats seals and seats; a burned or sunk seat kills the sealing and the flow. On a Pontiac V8, both are replaceable, and both are sized to the casting.
Butler stocks cast and bronze valve guides for Pontiac cast iron heads including a set for Super Duty 455 castings, plus Edelbrock manganese-bronze guides for D-port and round port heads and Edelbrock valve seats for both as-cast and Fast Burn chambers.
Browse Valve Guides and Seats Products
Popular Brands:
More About Valve Guides and Seats
1. Cast Or Bronze Guides
Both are here, and the choice comes down to how the engine gets used rather than how much it costs.
| Cast guides | Butler stocks a cast valve guide for Pontiac cast iron heads at 11/32" (.342") ID, .502" OD and 2 3/8" long, in sets of sixteen. This is the straightforward stock rebuild choice. |
| Bronze guides | Butler carries a bronze guide for Pontiac cast iron heads at 11/32" (.343") ID, .502" OD and 2 3/4" long in sets of sixteen. Bronze runs cooler against the stem and tolerates the side loading a high-ratio rocker and a stiff spring put into the guide. |
| Super Duty 455 | Butler lists a separate bronze guide set specifically for Super Duty 455 cast iron heads, at .342" ID by .564" OD by 2.280". Do not substitute the standard cast iron guide there. |
2. Get The Three Dimensions Right
Guides are ordered by numbers, not by engine size, and all three have to match.
| Inside diameter | 11/32" is the common Pontiac stem size, listed as either .342" or .343" depending on whether the guide is cast or bronze. That difference is real and it affects the finish reaming your machinist does. |
| Outside diameter | .502" is the standard listing for Pontiac cast iron heads. Butler also lists a .504" OD option for heads that have already been cut oversize. |
| Length | 2 3/8" and 2 3/4" guides are both listed for Pontiac cast iron heads. The longer guide supports the stem further up, which matters on a high-lift combination, but it has to clear the spring and the seal. |
3. Edelbrock Heads Are Their Own Conversation
Aluminum heads use pressed-in guides and replaceable seats, and Edelbrock splits both by port shape and chamber.
| D-port guides | Edelbrock uses separate manganese-bronze guides for intake and exhaust on D-port heads. They are not interchangeable, so order both. |
| Round port guides | the round port head uses a single manganese-bronze guide that fits both the intake and the exhaust side. |
| Seats by chamber | Edelbrock lists as-cast chamber seats for the older style non Fast Burn heads and a different set for Fast Burn chambers. The as-cast intake seat is 2.400" OD by 1.920" ID by .312" thick and the as-cast exhaust seat is 1.850" OD by 1.460" ID by .372" thick. The Fast Burn intake seat is 2.300" OD by 1.900" ID by .400" thick and the Fast Burn exhaust seat is 1.800" OD by 1.450" ID by .400" thick. |
| Know your casting | Butler lists the seats against specific Edelbrock casting numbers. Check the number on your head rather than guessing from the chamber volume alone. |
4. This Is Machine Shop Work
Guides and seats are parts you buy and a shop installs. Plan the whole operation.
| Order the seals to match | a machined guide takes a seal sized to the machined boss. Butler's Head Builder Kits specify PEP valve stem seals for machined valve guides for exactly this reason. |
| Seat cutting and spring pockets | if you are also fitting bigger springs, have the shop check the spring pocket at the same time. Butler notes that cutting valve seats may be required in a stock cast iron head with some hydraulic roller springs. |
| Do it all at once | guides, seats, seals, valves and a valve job are one job. Splitting them across two trips to the machine shop costs more than doing it together. |
Bring your castings or your casting numbers. The guide and seat dimensions are specific to the head on the bench, and matching them on paper beats finding out on assembly day.
Not sure what your Pontiac needs?
Email our tech team at tech@butlerperformance.com. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.