I’m in the process of changing intake manifold gaskets (stock cast iron intake) and was wondering if anyone has any thoughts on intake “port matching”. Thought while I have it off I can fudge it a little, but reviews seem to be mixed on this subject, do, don’t, don’t use gaskets to match, etc. Any advice? Good results/experience on why to do it or not?

If your car is strictly a street driven vehicle and the engine spends most of its time between 2000 & 4000rpm, then I feel that gasket matching is a waste of time. I did it to the heads and intake on one of our 455 bracket engines. We were only shifting at 5000rpm, so I didn't notice any increase in power or ET, over the as cast heads and intakes.

Pontiacs make most of their power from long stroke torque, in the lower rpm range. Now, if you wanna make 500-600hp and rev 'em on up to high rpm, with high flowing ported heads, forged rotating assembly, big cam and carb, then more airflow is needed.

But for reasonable, under 5000rpm street power, unported stuff will do the job nicely. Now, I have seen some ports that were really deformed looking, as cast. So, it would probably be a good idea to check 'em against a gasket, and remove most of the excess material from any of the really bad ports.

I've read that it is more important to match the intake port shape to the head port shape than to the gasket, so that there will be a smooth transition from the intake to the head. So, if the head ports are not gasket matched, then for some ports, gasket matching the intake port could actually make the mismatch between the intake and head port worse.

Obviously, it would be best to have both the intake and head ports gasket matched, for a smooth transition, and better airflow.

http://www.arkansaspontiacs.org/techstories/gasketmatch/gasketmatch.pdf

Maker sure the head port is bigger then the intake port. You don't want the air to hit an edge on the way in.

Use the orange locators in the felpro gaskets to line up your gaskets.

Need to index the gasket with a fine tip sharpie marker. Make marks so you can line up the gasket both vertically and horizontaliy. First I liine up the gasket on the head and trace the gasket along the top on the head itself and also make some tick marks up and down. Then line up the gasket on the intake and do the same.

I cut the crossover on the intake for a better alignment and so I can remove the intake if needed.

Thanks for the explanation and picture. I will attack this tomorrow. Thanks everyone!

Half way down this page I have lots of details on gasket matching the Intake. may help you?
http://www3.telus.net/68bird/engine_heads.htm

^ That's a good link .^

Some intakes I've had have casting flash on bottom of ports.
Unless porting heads and intake, or real bad alignment, I just remove casting flash and straighten the openings evenly.
Porting consists going up further in ports to really gain anything.

From what I've read when others have done flow tests on heads and intakes, they say that port matching on gains like 2% or there about a. Of course all are different and if it was real mismatched before and clean through after you might get a little more but really in the end it's not worth the trouble. Your best bang for the buck is said to be a bowl blend. Good for up tp 15% IIRC. Even that is not going to make a big difference on a stockish motor.

Don't believe everything you read on the interwebs

^ What he said. ^

Like which atomizes fuel better;

A polished port?
Or a ruff finish port?

Before you answer, there's been a lot of testing by many big name shops.
Last winter tried dimpling a junk cylinder head port like a golf ball.
My crude set up(lol) using wet/dry vac and spray bottle showed promising results...