Cylinder Head Porting

[rockmeupto125]

I've been toying with the idea of building up a naturally aspirated engine.  

 

Any of you hot rodders have some recommends for cylinder head porting?

 

I considered taking a stab at it myself as I half a couple spare heads and some half-assed ideas, but it might be better to work with a known quantity.

 

Thanks!

[ironmike]

Have you access to a flow bench? Head porting is almost as much an art as it is a science. You'd be wise to do some research before you start. FWIW, the XX heads (carb & FI) flow very well in the stock configuration.

 

http://www.motorcycleproject.com/text/cows-porting.html

 

http://dynobike.com/porting.htm

 

 

 

[mikesail]

The first article by Mike Nixon is very good indeed. Pay attention to what he says about valve seats especially. There was an article recently about dimpling intake bores to look like a golf ball, claimed a dramatic increase in air flow.

[rockmeupto125]

No flow bench.  And yes, its an art.  Enough so that I'm not willing to ship it off to someone who says they do porting without some serious supporting evidence, including feedback from you folks.

[superhawk996]

You could rig a 'flow bench' with a shop vac and vacuum gauge or a simple flow meter used to sync carbs.  Won't give you CFM numbers but will give numbers to work with.  You could start with just removing any sharp edges and blending the seats in, maybe back-cutting the valves; chuck it up on a drill press and grind/file while it spins.  Been so long since I looked in a Bird head I don't recall if there were obvious easy things to address.

[blackhawkxx]

I bet Northman knows since he built a non-turbo big motor.