I have my cylinder head at the machine shop and it was shaved 2 thou to clean it up (the straightest one I have seen). I am building a turbo motor that I will be throwing a lot of boost at. My question is will it be worth the money to do some pocket porting and intake and exhaust porting. I have talked to a few people and am getting mixed opinions. I know there is a wealth of knowledge hear and would like info from slant six folks.

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Raymond Flynn
Registered Six Offender!!!!

I think your on the right track,keep the block and head surface as thick as possible.This will help head gasket sealing,that seems to be a problem with high boost S/6 builds.As for head porting,I don't know too much,so I stuck to simple "goof proof" mods like removing obvious casting lines and the 3/8" dots in the roof of all the ports.I also blended the three angle valve job into the ports.

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V8?? We don't need no stink'n V8!!

Yea I want to keep the compression as low as possible due to the boost. I will also be O ringing the block to help with the head gasket situation. I was told by the machine shop that because I will be forcing the air in I did not need to touch the ports at all. I think that if I do some pocket porting and intake and exhaust work it will be better. I have been wrong before though

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Raymond Flynn
Registered Six Offender!!!!

You absolutely want to port the head. You want bigger valves too. Cranking up the boost to overcome restrictions in the engine adds more heat to the intake charge and requires higher octane fuel than a good flowing head with less boost.

Doug Dutra says the peanut plug heads are heavier and stronger than the earlier heads and hold a gasket better than earlier heads. I'm building a peanut plug head for my high compression 170.

Are you going to use a copper head gasket with o-rings or try to put the o-ring in the fire-ring area of a composite gasket?

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Joshua

I am using a peanut plug head # 3698447-4 with engnbuilder valves and will be using a copper head gasket. I have not given the composit gasket a thought. Do you belive one is better that the other? I am also useing a BH block number 2806830 10 which I belive is one of the strongest blocks from my resherch on the form. How far can I go on the porting? This will be a drag only motor 25 to 30 pounds of boost.

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Raymond Flynn
Registered Six Offender!!!!

I opened my head up in my opinion a secent amount i don't have me measurements infront of me but i believe something like on the exhaust side stock size was approx. .95 inch wide by 1.10 tall now are 1.10 by 1.30, intakes are now i cant remeber width i think i finished them at 1.15 inch by 1.30 tall. I measure all my ports as best i could to keep flow uniform and blended the bowl in the valve area and polished all the exhaust ports and smooth as possible and I have begun polishing the chambers in hopes of picking up some cc's in space. Im not a rocket scientist but i did do this head 10 times better than my last and that motor ran much faste then expected. Oh ya and this head is for my turbo motor that is still in progress
(PM me if anyone wants to shoot ideas back and forth on the turbo motor subject i'm always looking for knowledge)
Thanks, Kev

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Good choices on the head and block. I wish we had MLS head gaskets available. I'm going to suffer a copper head gasket too. The Aussie head gasket has a larger bore and is supposed to have a wider fire ring than a Fel Pro. I can see an o-ring working with an Aussie head gasket.

Engnbldr valves should be fine for a drag motor, but I'll be running Manley Severe Duty valves. I'm going to spin my 170 a lot higher than most 225s so I wanted stronger, lighter, single-lock-groove valves. I'll also be at maximum horsepower for much longer than a drag motor and worry about overheating an exhaust valve and dropping the valve head into the cylinder.

You really don't need to go very far on the porting. Most of the gains to be had are within an inch of the valve seat. You can raise and widen the port a bit, but I wouldn't take out much, especially on the exhaust side. With the heat from that much boost you're going to want plenty of material in the exhaust port so it doesn't crack.

The engine

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Joshua

Thank you for replying everyone. I will do some porting but not to much. The last thing I want is a cracked motor. I also read somewear that on a turbo motor porting the intake manifold 15% larger than the head is a good thing to do. Does that make any sense?

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Raymond Flynn
Registered Six Offender!!!!

I would check with SCE to see if they offer something for your /6. I talked to the owner at a drag race...and he told me instead of doing a O ring head or block...they have a head gasket that has that built into it. He said that they have one of those gaskets in a twin turbo'd Cummins diesel that is running 80lbs of boost. It might be worth the call.

The more you port the lower the boost psi to make the same hp. Go with the copper gasket and o-ring the block and yes, 15% bigger intake ports are better on N/A and boosted motors. Later.
Ryan

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10.74 @ 127.47 mph 1320 ft
6.65 @ 107.80 mph 660 ft

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