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How much power does porting and polishing get you?

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Old 02-04-2013, 06:53 AM
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Default How much power does porting and polishing get you?

Just dropped my 6.0 off at machine shop to get built got to talking with the guys there and they recommended that I get the heads ported and polished. How much power will I get with I do it?
Old 02-04-2013, 08:08 AM
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It really depends on how good the person doing the job is and how much material they take out. I have seen some port jobs that were botched give almost no improvement but I have also seen great head work that improved hp and tq ratings 150 to 200 hp. If he has the heads anyway you might as well have him shave them a bit if you are running NA
Old 02-04-2013, 08:18 AM
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the heads have been milled .035 , I took the motor to the best shop it town, got a full tour of facility and was very impressed by there big dollar flow bench and dyno room. So with a good machinest could i expect 25hp gain?
Old 02-04-2013, 08:23 AM
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With a great machinist that tests his work on the flow bench, I would assume you might be looking at around the 50 to 75 range with the finished ported stock 6.0 cast heads. Just have an intake and TB that can flow the same rate as the heads and an exhaust free flowing enough to get the air out just the same.
Old 02-04-2013, 08:28 AM
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pretty significant, but like said the skill or the porter is what determines the gains. if you dont know what youre doing you can end up hurting flow more than helping it.
Old 02-04-2013, 08:46 AM
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Are they pushing a porting that they do themselves, or are they just recomending you do that? Did you ever talk to them about the goals of this engine/car?

If you're going to do it, I would not just let some random shop take a dremel to your heads. I would send them in to a place like AI or TEA or Livernois for their cnc porting.
Old 02-04-2013, 05:18 PM
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What are they doing to the rest of the motor and what are your cam plans?

Head porting is probably the single most critical piece of adding HP.
Old 02-04-2013, 07:14 PM
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you can gain 20-30 from a really good port job.don't polish heads.what do they charge for porting heads ?
Old 02-04-2013, 08:54 PM
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Don West?
Old 02-05-2013, 06:50 AM
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ok here are the specs on my motor

LQ4 with milled heads (.035) w/ valve job; 224/224 .581"/.581" Cam w/ 112 LSA, Stock pistons and bore.
Old 02-05-2013, 08:25 AM
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Originally Posted by redtan
Are they pushing a porting that they do themselves, or are they just recomending you do that? Did you ever talk to them about the goals of this engine/car?

If you're going to do it, I would not just let some random shop take a dremel to your heads. I would send them in to a place like AI or TEA or Livernois for their cnc porting.
This x2.

The quality of the valve job and port work is so important it's incredible the differences I see in power numbers with identical camshafts, identical compression and identical exhaust set-ups. When it comes to the cylinder heads the heads can have identical port volume, valve size and combustion chamber volume, but the dyno numbers and track numbers are vastly different.

Just because you're getting a set of heads, "CNC ported" does not mean that all are created equal. A lot of times when a customer has a set of heads that have been ported then don't make the numbers they wanted they blame it on the camshaft or the tuner.
Old 02-05-2013, 09:39 AM
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Question
How much power does porting and polishing get you?

My 2 cents (answer)
The answer to this question greatly depends upon the entire engine build, goals and usage. For a stock rebuild or or even a good mild street/strip build, A good set of stock heads (good valve job) will take you pretty damn far and will not be the limiting factor. Next a good set of stock heads with mild porting, even if done locally will usually provide a nice improvement and solid performance.

I am some what new with the LS engines, I base of lot of my thinking on things I have picked up and learned from building racing engines over the past 30 years. That said. The head design on the LS engines is one of the best production heads out, in bone stock form it out performs many of the ported and even aftermarket sbc heads that many of us have worked around for years.

RockCrawler To directly help with your build, seeing that your cam and build is on the mild side. I would make sure your heads have a good valve, and then go have fun. I feel that anything more than say a mild cleanup port job, may not be worth the added cost.
Old 02-05-2013, 11:18 AM
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My original motor had a Streetsweeper cam in it, stock unported heads. It made 405 rwhp. The new setup made 432 rwhp, differences are smaller cam and my stock heads were ported by AI. So I gained 27 rwhp with this new setup. Same exhaust and intake setup. Not exactly showing ported heads only but some great results with ported heads.
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