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Old 06-12-2006, 09:11 PM   #1
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Default Question about heads.

Ok so i got some spare heads for my car... im going to toltaly rebuild them and make them better.

So what are some good brand/pars to get for them?
want to make them better then stock but with out speding all my money

also wat do you guys think about porting & polishing them?
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Old 06-12-2006, 09:19 PM   #2
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I'd suggest staying away from porting them if you aren't doing a custom cam or PEM'*.
Polishing won't hurt as at will remove the roughness in the runners and revving will be smoother with slightly better response. For power gained from polishing you might see 2-5 HP, but nothing overly noticable. I am supercharged with a few more mods than you have and although I'm having a set of heads rebuilt right now I asked that no porting be done, but I did request a light polishing.
You might want to ask about getting new springs as the originals may be a little 'soft', depending on the miles on them.
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Old 06-12-2006, 10:43 PM   #3
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yup i was going to re do every thing.. any brand for parts??

or what types ??

im clueless when it comes to head stuff., n ever done it befopr , but i want to learn so i figured this will be a good first start
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Old 06-12-2006, 11:05 PM   #4
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As far as the porting goes, I would get 3 heads. One to practice on and the other two to really really do well. You'll need acess to an air compressor and die grinder as well as a standard abrasives kit.
I suggested a 3rd head because it'* really important that you port everything EXACTLY the same. Otherwise you'll be helping one cylinder while hurting another and get messed up O2 readings. That will make your car run bad and impossible to tune..
Gasket match the intake ports.
Take off minimal material especially on the short side radius'. (the tight curve at the valves) And keep the general shape of the exhaust port. Don't try to port it out to the exhaust manifold. If ported wrong, the exhaust will flow less and you woun't have the benefit of the 'step' from the port to the exhaust primary. (keeps everything flowing in one direction and pulls the flow down into the primary.
Don't grind near the valve seat and get a valve job when your finished.
If you want to mill the heads to raise compression that may be a good idea too. I'd suggest milling 0.020" to bump compression up a few tenths. At 0.020" your stock hydraulic lifters will still be able to compensate.
Have somone press in new valve guides.
And as far as hardware goes I have no idea.
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Old 06-12-2006, 11:25 PM   #5
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A practice head is VERY important. Call it a requirement.

Probably the single-most critical point I can share with you is to keep all 12 ports as close to the PERFECT dimension of each of the other 5 ports of it'* type.

If you have one intake port slightly larger than the other five, it will tend to run lean. 3 rich and 3 lean would suck for power, even in small amounts it can add up quickly.

In my LIM work, I took great pains to insure that all 6 ports were PERFECTLY matched in size not only to the heads, but to each other as well. Had I not done that, I would have defeated the potential gain that I had in my flowmatched injectors.

Remember that you have only ONE oxygen sensor. Not 6.
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Old 06-13-2006, 10:37 AM   #6
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Quote:
Originally Posted by willwren


A practice head is VERY important. Call it a requirement.

Probably the single-most critical point I can share with you is to keep all 12 ports as close to the PERFECT dimension of each of the other 5 ports of it'* type.

If you have one intake port slightly larger than the other five, it will tend to run lean. 3 rich and 3 lean would suck for power, even in small amounts it can add up quickly.

In my LIM work, I took great pains to insure that all 6 ports were PERFECTLY matched in size not only to the heads, but to each other as well. Had I not done that, I would have defeated the potential gain that I had in my flowmatched injectors.

Remember that you have only ONE oxygen sensor. Not 6.

so i really shouldn't try the porting or polishing my self then....

But i could judt have some place do just that, and ill build the rest

I dont want to mess up my heads, i have all the tools needed i think.. but iv never done that and i did know how close they had to be... :(
So i think i will not try that but i will have someplace do it if it doesn't cost to much, if not ill just clean them up & replace parts and bult them on..
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Old 06-13-2006, 11:45 PM   #7
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I'd use them as cores on a good set of aftermarket heads such as our stage 3'*. Seriously, if you don't know what your doing you can ruin a pair of heads really quick, and no amount of work you do yourself will ever come close to what is available. Airflow can be severely impaired by improper porting.

If you don't want to spend a lot of money I would do another airflow mod such as a cam first.
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Old 06-14-2006, 12:38 AM   #8
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Quote:
Originally Posted by Rogue
I'd use them as cores on a good set of aftermarket heads such as our stage 3'*. Seriously, if you don't know what your doing you can ruin a pair of heads really quick, and no amount of work you do yourself will ever come close to what is available. Airflow can be severely impaired by improper porting.

If you don't want to spend a lot of money I would do another airflow mod such as a cam first.
You have parts for L27'*? i thought you started only with Series 2...

how much is the cam?

also is it easy to just polish the heads without hurting them?
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Old 06-14-2006, 12:58 AM   #9
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Quote:
Originally Posted by bandit
Quote:
Originally Posted by Rogue
I'd use them as cores on a good set of aftermarket heads such as our stage 3'*. Seriously, if you don't know what your doing you can ruin a pair of heads really quick, and no amount of work you do yourself will ever come close to what is available. Airflow can be severely impaired by improper porting.

If you don't want to spend a lot of money I would do another airflow mod such as a cam first.
You have parts for L27'*? i thought you started only with Series 2...

how much is the cam?

also is it easy to just polish the heads without hurting them?
He'* suggesting you find a vendor or shop who can properly do headwork for a Series I would suggest finding a good reputable performance shop near you and tell them you'd like your heads ported, but to keep the original shape, rather than to make them round or oval (not sure off hand but I think SI'* have 'D' shape runners, but then again it may the SII I'm thinking of). Either way you'll want to keep the original shape.
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Old 06-14-2006, 06:09 AM   #10
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bandit,

Head porting is serious business. If you want your heads ported professionally, I have a personal friend that is a machinist in Missouri that can do them for you. Send me a PM if you're interested.
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