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Old 04-30-2002, 04:45 PM
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Red face head rebuilding/porting

hey i got a 302 and in going to rebuild the heads
need a few tips im planning on going with larger valves and doing the porting myself any tips on what to do and what not to would be extremely helpfull cause ive never done a port job before

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Old 04-30-2002, 07:08 PM
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Do a search on head porting on the web and you will get all kinds of info, what they don't tell you are some of the secrets that have been learned from experience, here are a few I know.

-Buy carbide cutters and save the cartridge rolls until the very last finishing operation, the work goes much faster.

-You will need a good die grinder and a full face shield, wear safety glasses under the shield too. Those cast iron shards are nasty. Ear plugs and muffs will be mandatory or you will go nuts or deaf after 12 hrs if you are using copmpressed air.

-Buy a couple 1/4" drum cutters and a 1/2" drum cutter as well as a couple ball cutters of different dia. A tulip shape cutter and a tree shape is handy too. Buy all of them in double cut configuration, it takes less pressure to cut.

-Use aluminum duct tape to protect the valve seats, use a few layers for extra protection. You can also use it to scribe your lines onto so you can grind to them when laying out the ports.

-Remember whatever you do to one chamber or port you have to do to the others, if you spend 10 hours on one port and chamber you are going to be doing this for a while. Don't ask how I found this one out, two weeks of summer holidays are gone from my life because I was ambitious-at 16 hours a day! You can't see the ports and chambers from outside the engine either!

-Don't take out too much, stay to the short side radius and just blend the nasty obstructions and match the ports.

-Don't touch the quench part of the chamber on wedge chamber heads, just rough polish the chamber and then leave it alone.

-Use a little brush to remove shavings, compressed air just gets it in your hair, eyes, clothes, underwear, ears, shoes.........

-You can use spray dye to match your intake ports just test assemble the engine (use your gaskets)and use a vacuum on the intake port from the piston side and spray into the intake manifold, it will mark your ports just dandy.

-Blend around the valve stem protusion to streamline it in the port and use a valve with the head cut off to protect the guide interior. Do not remove the protusion!, this is your valve support!

-Stick old spark plugs in the plug holes to protect the threads.

-The area just below the valve head and the short side radius are where all the gains are to be found, just rough polish the outside radius's.

-Most cylinder heads can accomodate a 1/16" removal inside the ports and that's all!!!!!

-80 grit is just right for roughness of finish.

-Do your valve job after the porting in case you slip and hit the seats-you will!

Let us know how you make out when your done, some pics would be great!

[ April 30, 2002: Message edited by: 4 Jaw Chuck ]</p>
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Old 04-30-2002, 07:28 PM
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get a set of 69 to 73 351w heads they have bigger valves alreadty and larger ports open up the exhausts a bit and your good to go. www.dscmotorsports.com has these heads fairly cheap or try a bone yard.small chamber/big valve heads have the large spark plugs, with 60cc chambers the compression goes up most later 302 heads have 69cc chambers, you will need a special set of head bolts to do the swap and they make intake gaskets for the larger ports this would be cheaper than modifying 302 heads or buying aftermarket and looks stock
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Old 05-01-2002, 11:49 AM
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Standard Abrasives has a pretty decent DIY head porting article. It's located here: <a href="http://www.sa-motorsports.com/diyport.htm" target="_blank">http://www.sa-motorsports.com/diyport.htm</a>
They give quite a few plugs for you to buy their products, but that's to be expected! 4JC also had some very good tips.
Good luck!
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