Aixtreme89

I have tried to search this and find pictures, but info is kinda limited. I have a set of 03 DOHC heads I want to work on while there sitting around on my work bench. I would like to know what are the KEY areas to work on, and what not to touch. I know many people are going to get the urge to say just send them off to a professional; but no thanks its not worth the money for me. I would like to do all the modification myself I can with the most benefit. Besides having a valve job done, id have that done by a machine shop.

I have heard many different ideas thrown around. Sean Hyland in his book recommends for the 03 intake port to "open the seat up to match the factory bowl machining, and work on the short side radius to improve the transition." Is this a good minor modification I can make? There probably is only a 1/4" of material on the short turn radius before entering the water jacket so this has to be minimal. Then Sean Hyland doesnt make any further recommendations for the exhaust port. Should this just be sanded smooth to a mirror finish without disturbing the port shape?

Then Ive read not to gasket match either port, but possibly port match the intake to intake port? What it I were to just port around the fuel injector to improve flow from that ridge into the port?

I have gathered from my reading that a 3 angle valve job would be the most beneficial but that is the most expensive route I would want to take.

Would un-shrouding a portion of the valves in the combustion chamber yield good results? There isnt much material to work with and very tight not forgiving area.

Has anyone tried to clean up the valves, by back cutting or just smoothing the finish from the valve seat to the valve stem?

As for porting the intake, I have an 03 Mach intake. Has anyone attempted this? Ive heard just to open the six guides leading to the runners below, as much as you can in the upper portion of the lower intake then port match to the head port. Then to cut it open and smooth the beginning of the runners and weld in new material and shape them.

I would love to hear any comments that have some good insight into this topic. Preferably with pictures to help. Thanks!

nickmckinney

I know you don't want to hear it but if you don't know what you are doing you can lose flow just as fast as gaining any. You go too far in those heads the midlift flow will go down while the high lift goes up and the car runs slower that way unless you have a 500 lift cam. Find someone with a Serdi that can do a radius valve job as it will pick up the most flow gains with typical 4V cam lifts vs a 3 angle. If you run a tighter spec bronze valve guide you can narrow the 45 angle for a flow gain as well.