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Intake Manifold Gaskets
Pontiac V8 Intake Manifold Gaskets
Two Questions, Four Answers — Intake Manifold Gaskets for Pontiac V8s
Intake manifold gaskets for a Pontiac V8 are sorted two ways at once: by the casting era of the heads and manifold, and by the size of the intake port you are sealing. A gasket that is right for a 1963 389 is wrong for a ported Edelbrock head, and a gasket sized for a large port will hang into the runner on a stock head.
Butler splits this category four ways so you can land on the right one: early cast iron 57-64 (non-SD), later cast iron 65-79 (non RA4/SD 455), RA4 and large port cast iron plus out-of-box Edelbrock, and ported Edelbrock, aftermarket and Ram Air V.
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More About Intake Manifold Gaskets
1. Question one: what era are the castings
Pontiac changed the intake face partway through the run, and the gasket follows the castings, not the displacement.
| 1957-64 cast iron, non Super Duty | the early pattern, covering the 1957-60 engines and the pre-1965 big-inch and 326 engines through 1964. |
| 1965-79 cast iron, non RA4 and non SD 455 | the later pattern, and by far the most common. This is the standard port gasket used on the vast majority of D-port Pontiacs. |
| The Super Duty and Ram Air exceptions | Super Duty and Ram Air IV engines are called out separately on purpose. Do not assume a year alone puts you in the right group. |
2. Question two: how big is the port
Once you know the era, the port size decides the rest. Butler's split runs from stock through fully ported.
| Standard port | the factory D-port opening, a 2.20" x 1.18" port in .060" thickness in the common sets. This is the 65-79 group. |
| Large port and out-of-box Edelbrock | Ram Air IV, large port cast iron, and Edelbrock heads used as they came out of the box get a 1.125" x 2.240" gasket with extra material on the upper side in case you port later. |
| Ported Edelbrock, aftermarket and Ram Air V | once the heads are CNC ported or you are on an aftermarket casting, the port grows again and Butler matches the gasket to the airflow number of the head. |
| Why it matters | a gasket smaller than the port puts a lip in the airstream. A gasket bigger than the port exposes gasket edge to intake charge and can wash out over time. Match it, or cut it to match. |
3. What comes in the set, and what to do about the heat crossover
The stock-style intake sets are more than two gaskets, and that is where most of the useful content is.
| Heat crossover block-off plates | several of Butler's standard sets include block-off plates for the exhaust heat crossover, along with restrictor plates. Blocking the crossover keeps heat out of the intake and the carburetor on a performance engine; leaving it open is the right call for a stock drivability rebuild in a cold climate. |
| Intake to timing cover seal | the better sets include this seal. It is the one people find leaking six months later. |
If you are not certain which group your engine falls in, measure the port opening in the head and count the years on the castings before you order. The four subcategories exist so you do not end up with a large port gasket on a stock 400.
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.