Which Intake manifold gasket

furrystump said

I believe that is backwards. Ok for manifold to be slightly smaller. You just don’t want a wall at the transition. A small jump ok. Running into a small wall bad.

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No, that’s exactly right. You never want the intake smaller than the head. You can test that is 5 minutes on a flowbench to see it.

You never want a dimensional change in the port unless you can’t avoid it or you are talking about taper in the runner.