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Project: Sabriel
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12,507 Posts
Discussion Starter #1
ok, im taking the heads off my '95 CPI to be ported and polished soon. what exactly does this entail asking for at a machine shop? are there certain specs i should get, a maximum/optimum port size for the CPI, ect ect? Also, what kinds of gains am i looking at (with JBA headers, big exhaust, K&N fipk, and JET chip fgured into the equation)?
 

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Early Member
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3,114 Posts
A port and polish on the heads, is opening the intake ports up to a specific size, the blending of the ports (polish) so they are smooth. Headers and big exhaust will make good improvement as long as the exhaust is not overly big. I don't think a port and polish is going to be beneficial with a stock cam.
 

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Project: Sabriel
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12,507 Posts
Discussion Starter #3
is there a good size i should have the heads ported to? also, what would a good cam be for daily driving/mudding?
 

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2nd place is the1st loser
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238 Posts
A good port job like gasket matching is good.And the gains are worth it.Thats why the 96 up heads are so good.The intake and exhaust runners are bigger so they flow better.They also have a better combustion chamber shape and design.Anytime you open up the ports to get more air in and out is a good thing.Be sure to port both intake and exhaust.You can see as much as 20 hp pocket porting.And adding the rest of what you said will only compliment the port job.As long as your facory cat converter is not stopped up it will give you all the backpressure you will need.
 

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Project: Sabriel
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Discussion Starter #5
pocket porting? also, whats the rough price for a port and polish?
 

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For a price, I would just call around to different shops.
 

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there is a guy that live in my area who does it as an extra side job, he charges 350 for the porting by hand, hes beter b/c he'll go farther than a machine shop will (within reason though). and the machine shop costs 150, so for $500 you could get some great ported heads and see a cignificant difference, my friend had his z28 head done, they have like 275 stock hp, he had it dynoed at 251 rwhp, he did lond tube header and had the heads done by the same guy and when it was redynoed he was making 289, so there are some great gains of getting them done.
 

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