fast66

No Starfury, Match porting is done by dummy fitting the mating components using engineers blue to mark the surfaces. This shows what needs to machined on either component. Your version takes no notice of theshape of the port and its natural flow during transition between one component and the next, and simply mimics the shape of the gasket.
Most gaskets are made larger than required and not necesarrily the correct shape, and when using the gasket porting method, you get a localised large port area which actually restricts flow. The best flow is achieved by a port that does not vary in diameter/cross section. (as much so a practical).

67mustang302

Definately grind down those retarded air injection LUMPS in the exhaust port. Totally unneccessary. Technically, my AFR heads are smog heads, but they just have holes rather than gigantic turds hanging into the ports. And port matching will really help as well, just make sure you leave a small overhang on the intake, and the head when going to the exhaust. IE you want the intake manifold exit to be just a bit smaller than the intake port on the head, and the exhaust port on the head to be a bit smaller than the exhaust manifold, like going through a series of openings, from smaller to larger. The minor overhang on street vehicles helps with reversion in airflow at low speeds, and will keep mileage and part throttle torque up.


Ooops, edited, I meant the exhaust port on the head should be a bit smaller than the manifold.

straw1628

Thanks for all the info. With all the talk about grinding, would it be easier to pick up a set of non smog heads, or would that get me away from originality. Thanks

JMD

With all respect for youroriginal question, you don't really need to do anything to your heads to receivea reasonable return on your proposedperformance parts.

If you are reasonably happy with the performance ofyour car as it is now, you will be more pleased with your car once you change the parts.

Will porting your heads make more power? yea. Would Gt 40 heads make more power? yep. Would aftermarket heads make even more power? yep.....

Do you really need any of it? Given your goal of a little more performance I don't think so.

Go with your bolt ons, remove the air tubes. If you find yourself stilllooking for more power, change your heads! By going this route, if you later decide you need more power, as far as duplicate work goes, you will be out of pocket for a little labor, some gaskets,and probably a second replacement cam shaft.

The reason for the second cam is that the ideal cam for the stock heads and the ideal cam for aftermarket heads will not be the same.

straw1628

JMD,
Thanks for the advice, I think thats how I am going to go.

67mustang302

I edited my previous post, minor but significant error, the ports on the head for the exhaust, need to be a bit smaller than the exhaust manifold/header.