Home Porting...Watcha Think???

You're on the right track, but you need to get a gasket and match the port exit to the gasket hole. Be sure to get the alignment right.

use a micrometer thell tell alot

FLA5.0 said:

how could you possibly know if they are all the same?

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this is why professional porting and cnc porting is so expensive. the only ways to tell are with a ton of experience or a flow bench.
try as hard as you can to get them similar, but they won't be "perfect" with out flow testing them. that's one of the things you have to compromise on when you port at home.

Micrometers will only help with an area of externally measurable thickness like the pushrod hole squeeze on the intake side. For water jackets you need sonic testing and even then I'm not sure of it works on a complexly cast item like a cylinder head. Also, CNC porting is really only expensive because most machine shops charge $75+ per hour. Since Power Heads deals with the public, they tack on even more just because they can. It doesnt take 6 hours for them to port a set of heads.

The best reason I can come up with for the exhaust port bumps is to provide a flat spot for drilling the hole down the middle. It makes manufacturing easier. As far as breaking through into a water jacket, you have to be conservative or just not worry. It helps if all the ports have the exact same amount removed, but short of trial and error and alot of flowbench time only CNC porting can do that. Most all the heads are close in dimension and tolerances, but being sand-cast none are identical.