Intake manifold to head port mismatch

[WFarm]

I pulled the valve covers on the 454 and recorded the casting numbers on the heads. As I posted elsewhere recently, the engine is a 1971 LS5 365 hp originally in a Chevelle.

The vintage Weiand intake manifold (PN WCPSQ) is for the large, rectangular port heads. My heads are oval port (casting # 3993820, 1971 365 hp LS-5, Open Chamber, 113cc Oval Port heads).

The engine runs great; no known issues. Is this port mismatch to be concerned about?

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[fast 99]

If it runs fine don't fix it. However, larger intake to smaller head port will be detrimental to performance. Square edge on head will upset air flow.

 

[WFarm]

If it runs fine don't fix it.

Exactly! If it ain’t broke don’t fix it, lol. But I was wondering if there was any long term detrimental effects. A reduction in performance is something I can live with.

 

[fast 99]

I wouldn't think so. However, it would have more power [torque] with the correct intake.