polish and port

as soon as my garage is finished i would like to polish and port my manifold. I have a edelbrock performer rpm manifold. I have a book that tells me how to do this. my question is how much hp will i gain. I am running a 350.

Do you mean match porting the intake to the head, or ??? Just doing the intake I don't think would account for an appreciable gain in power...... Most of the problem areas on the intake side are matching the ports and some pocket porting... Biggest gains on an at home job with no flow bench to equalize things would probably come on the exhaust side of the head.....

You dont want to polish any thing on the intake. I read a couple articles on doing it at home and where are areas that need real attention. You know cleaning up what you got. If your looking for big flow numbers you need a flow bench.

I am talking about a gasket match port and polish. sorry i was not clearer before. They have a step by step guide in the new issue of chevy high performance.

you dont want to polish anything on the intake....unless its the outside?? You polish the exhaust.

thanks big truck. that clears it up for me.

Unless your talking 1500hp plus with 30 lbs of boost.....:D

oh how i wish :D :D

That intake manifold is most likely ok . It's if your head ports look like this . Then they need the intake gasket match porting . :eek:

Check out a book from SA Design, titled "how to build max performance chevy smallblocks on a budget". It's written by David Vizard, and has some good info on porting & polishing.

I got mine at a book store, but it's also available at cartechbooks.com.

Adam**)

Here's a couple pictures of basic port work. The intake and heads were matched to the gasket and the ports smoothed out some (but not polished) back into the manifold and head ports.

I also polished the outside of my intake and will never do that again. Buying one factory polished is a great investment IMO. :LOL:

Kitz

beautiful jon thanks so much for the pics.

double post

heres a start....They also sale porting kits to get you started , Summit and Jegs do also.


Mondello Performance Products-Head Porting At Home

Mondello Performance Products-Porting at Home

I barrowed the first pick from above to show basicly what I started with and the finish product. They are both stock cast iron heads. Do plenty of reading before doing this you can ruin a good thing real quick. Another thing is that its real time consuming. If you are still planing on just port matching your intake it should be no problem.http://www.clubhotrod.com/forums/att...lish-20006.jpghttp://www.clubhotrod.com/forums/att...-heads-024.jpg

The first thing I will say is stay out of the valve seats.
To many people have given me heads that require a few new valve seats because someone has gotten to wild with the die grinder.
For cast iron you will need to invest in some carbide cutters.
They are a little expensive but should last you forever.
Then you will need a porting kit.
I would try Goodson for your porting supplies.
I would first remove all the parting lines and knock off any casting flash if there is any present.
Think radius/smooth.
No sharp turns of rough edges.
In a street car I would try and keep the finish in the 120/180 on the intake side to try and keep all the air/gas atomized.
The exhaust should be made very smooth.

thanks denny

You could check out your tools on some junk heads before going after the good stuff.

The technique uses a lot lighter pressure with Aluminum.....

well i have never worked with aluminum before but i have etched alot of glass and i have a pretty steady hand. figure that when i start it i get real confortable and take my time i should be okay.

i know about the gaskets but what do i use to scribe it with. they show what looks like a punch but do not tell me that they are using.

so by doing all this i should get a better burn of the air gas mixture?

so will this also help with any fuel that might excape through the exhaust. my car runs a little rich. if i dont run it that way it has a bad lope.

thank you denny for taking the time to inform me of all this. you are very kind. i am learning so much. you have made it very clear. i am the type that wants to try everything i read and do not some times think it out well enough. now if i can get my town to come off the zoning and building permit for my garage than i can get started.

yes you were very thorough. i really enjoy your drawings as it helps me see with my minds eye how things go if that makes sense.

gotta love a american made combustion engine.:)

Hi JYG, So far nobody has said "why". You want to match the ports to the manifold on the intake side and leave the intake ports in the head a little rough to maintain enough turbulence to keep the fuel droplets homogenized. The ports on the exhaust manifold should actually be a little larger than the exhaust ports of the head to provide a little ledge around the exhaust port to prevent "reversion" which is a slight tendency for exhaust gas to go back into the chamber. The exhaust ports in the head are where you want a smooth surface because the hot gases expand and need as much help getting out of there as possible. I know the theory, but paid $200 to have the exhaust ports smoothed out on my 350 "882" heads because it takes SKILL to do it right without holing through to the water chambers. I know the theory but don't have the skill so I paid a pro!

Best Wishes,
Don Shillady
Retired Scientist/teen rodder

Quote:

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they show what looks like a punch but do not tell me that they are using.

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Sharpen an old screwdriver on a grinder and use it as a metal scribe.

they guy who does my heads buys new cutters for every set of heads.

When porting out heads the Bowl area or also called valve pockets . Is were the most HP gains are . But the ports still need to be worked for the full HP potential . :cool:

You are very right Denny W . If you make an intake manifolds ports bigger then the head ports . It would be Like air flow hitting a wall . And then there will be a drop in The power . It is always better to have the head intake ports just a slight bit larger . COOL

Did you start on your port/polish job?
Here's a decent overview article I ran across.

DIY - Basic Cylinder Head Porting -Standard Abrasives Motor Sports

Excellent reference SBC. Start to finish, zippety-do-da. :)