Replacing intake manifold gaskets. Quick help needed!

[66DC]

Does this look right to you all?

I found phenolic spacers between the two old gaskets, but when I replaced them with new Victor Reintz, it looks like the inner diameter is quite a bit more narrow than the spacer and even the manifold.

[javadog]

No. You want the gaskets to be the same as the port diameter. In a perfect world, the intake runner, spacers, gaskets and ports would all be the same diameter and all would be concentric.

Anything else and you reduce the airflow and thus, the power produced.

JR

[66DC]

Would it be OK to cut them to fit? The catalog says these are the right gaskets, but clearly they are not.

[javadog]

That's one option. You might find it difficult to get a nice, smooth round cut. If that were my engine, I'd buy another set of gaskets. I don't care what the catalog says, those aren't right.

JR

[66DC]

Thanks. Looking at the options, I see I need the 38mm diameter ones that come on the 911S -- except I don't have an S. Maybe I just have S heads. One more mystery thanks to the previous owner.

[javadog]

Might want to look a little deeper to see exactly what you have... If you have S heads, maybe other stuff got changed, too.

JR

[T77911S]

measure the port diameter

[john walker's workshop]

Stick a rag down the port and with the gasket sitting on the spacer, use a sharp pocket knife to carefully carve out the center. Mechanics 101.

[Targa Me]

Thanks for the idea, John.
Sometimes the painfully obvious, is not so obvious... to me anyways.

[zedsn]

Pull the gasket and mark the material with the insulator to the required diameter and use a box cutter with a razer blade to make the larger diameter circle. Won't take a chance of getting any foreign object in the intakes that way.