Don't go nuts. These 16-valve heads are pretty well flowing to begin with. A mild porting is all you need.

Take your intake and exhaust gaskets, place them on the head where they will be mounted and score the head in the port area where it may overlap the gasket openings. Then, take off material to that line. Do the same with the intake and exhaust mainfolds. That's called port matching.

Where the valve comes through the port you can round that off a bit. Also clean up any rough casting spots to smooth things out. Leave a rougher surface on the intake side (80-grit) and polish the b'jesus out of the exhaust side. Mine is mirror smooth. You can also polish the shroud area (the area where the valve faces are seen) and remove a little material from the shroud rim around the exhaust valves (that's called tapering the shroud). Be sure not to go beyond where the head gasket seats though. Also, put an old valve in the seats when you're working on the shroud area so you don't mess up the valve seats. DO NOT TOUCH THE SEAT AREA OF THE VALVE SEATS! If you are very careful you can open the diameter of the valve seat if there is a lip where it meets the head inside the port.

DON'T OVERGRIND THE VALVES. A simple lapping is all you need. The valves are Stelite coated and if you overgrind them the coating will be removed and they will be junk.

Lastly, I cut some Somender-Singh groves in the last head I did. I can't say whether they made an improvement on power because I had ported the head at the same time. But, I am getting way better gas milage with them.

Hog out and polish the exhaust manifild as well. There is a lot of meat that can come off there, and polishing it will help the flow a lot.

Check out the guide at the link below.



posted by 169.226.135...

Standard Abrasives head porting guide.

• more ?'s on head porting...., Smeter, Mon, 18 Dec 2006 14:53:25
  • Re: more ?'s on head porting...., SWEDISH DYNAMICS, Tue, 19 Dec 2006 14:39:31
  • Re: more ?'s on head porting...., chrisx, Tue, 19 Dec 2006 10:52:28
  • Re: more ?'s on head porting...., turbocon86, Tue, 19 Dec 2006 06:49:53 <-- Viewing This Message
    • Re: more ?'s on head porting....????, John N, Tue, 19 Dec 2006 17:07:15
      • S-S Grooves, turbocon86, Wed, 20 Dec 2006 08:37:38
        • Re: S-S Grooves -- Great ????, John N, Wed, 20 Dec 2006 12:50:10
        • Why is it that I hear people hot rodding the car then.., Inga , Wed, 20 Dec 2006 09:57:43
          • We are from the same school..., turbocon86, Wed, 20 Dec 2006 10:58:39

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