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Porting heads....

Iceman6669

Iceman6669

The Boss
Staff member
So I recently aquired myself a set of stock L67 heads that I am going to clean up and attempt to port and polish. I have done lots of reading and seen lots of pics. I just figured I would start this thread so as if anyone has any pointers or advice I can learn it BEFORE I make a mistake...
 


Also what tools did you use. IE what bits and such. I know that using a die grinder will be much better then a dremmel.
 
Eastwood porting kit.

Be aware of the shaft position at all times.

Be careful around the seat and the guide. Unless you're having new ones installed.
 
Dremel works great but get the flexible extension, it allows you to get into the ports well. For street heads, you don't want to change shape of ports, but rather clean them up getting rid of casting flash, pay most attention to the valve "bowls", blending and smoothing is what you want to do. Polish the combustion chamber completely, not mirror smooth, but clean and smooth to avoid hot spots, this is the biggest deterrent to "knock", important on Supercharged engines. Get all the little Dremel rotary files you can along with the sanding barrels and flapper wheels. Wear a dust mask too.
 


Perfect time to buy a rotozip with flex shaft. Should have enough kick to do it.

Step 1, have the heads cleaned and magnafluxed. If they fail fluxing..you can stop there.
 
It's a good idea to get it done. Take off as little as possible to get them flat. If you need to take off anymore than .025", I would recommend finding a different set of heads, or you might have problems keeping headgaskets from popping out.
 
Well I was going to attempt it myself on a mill... And honestly I was doing it because someone told me it would boost compression... I was also planning on running thinner head gaskets..,
 


So after long thought, I don't think I will deck the heads.... WAY too critical. Put I was thinking I might spray the intake and exhaust runners and valve bowl with dyechem before I start so I can see how much I have taken off and where I haven't touched it at all.
 
The port is cast black/gray so when you hit it with a die grinder it will turn it into shiny metal, you wont have to worry about seeing what you ported. I would get some intake gaskets and gasket match the heads and then the intake manifold all to the same shape/size. I would save up and get a valve job done last because you will probably nick the valve seats if you are doing the bowls. Get some cone/curved stone bits to take out the casting marks and get the shape, then hit it with some sandpaper bits to smooth it out and finish it off with some kind of polishing bit.

I've always heard the exhaust ports give the best gains on these heads, which is good because they are the easiest to reach :th_winking:

have you seen the head porting guide on clubgp? if not go find it.
 
when i did my heads, i had them milled .005" and i am running .052" cometic 4 layer head gaskets. that is .010" thinner than stock.

so a total of .015" thinner. no probs here.

also i grinded out the casting in my exhaust ports and buffed the bowls. There was as much as a 1/4" stick out in the exhaust ports.

Then finished up with a 3 angle valve job.
 
Here is what my heads look like after MagnaFluxing them
1017700_626746917349321_1058808739_n.jpg
 

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