Worth the effort?
 

Was finally getting around to reinstalling my exhaust and was getting the gasket oriented properly and noticed that there is a lot of material that could be removed for a better "Gasket Match" to the AFR 265 heads. They are EMI Thunder cast exhaust and not true headers so I'm not sure that it's worth the effort. Lets set aside for this conversation that I have never ported anything, just want to know your opinion on whether this might be worth the effort or not.
Thanks for your input.
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Now, Lets see the gasket on the heads.

Good call. That's why I come here with my questions. My memory was that they fit the heads pretty close because I use AFR gaskets but maybe not so much.
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I think if you start grinding on that exhaust manifold it gonna get pretty thin in a few spots...I might just bevel that edge a touch..I'm not a total boat performance guy , but built race engines for cars so take it for what it is worth..

I'd just put it back together as is and go boating!!!

Imo the heads look smaller than the exhaust.

I don't think there's enough there to notice any difference.

Put it back together and go boating…

You could trim the gaesket in the upper corners, but otherwise you're GTG.

Having the exh port a little smaller helps out with airflow reversion on overlap.

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I cleaned up the ports on my powerflows to match the Promaxx’s. It was quite a big area. At least I was feeling like I did something. Who knows!