Milling heads 64cc to 62cc
Probably not. A 2 cc change is not much. The GM ECU should be able to compensate for that small a change.
The real question is WHY?
Why are you spending money to make such small change?
You will not be able to see any gains from JUST that mod.
If the reason is you over heated the engine and your heads require milling to straighten them then you tune might be in question anyways...
What's your set up and why are you wrenching on it?
The real question is WHY?
Why are you spending money to make such small change?
You will not be able to see any gains from JUST that mod.
If the reason is you over heated the engine and your heads require milling to straighten them then you tune might be in question anyways...
What's your set up and why are you wrenching on it?
Thread Starter
Launching!
Joined: May 2010
Posts: 274
Likes: 1
No overheating, the valvetrain just needed a refresh and I have a small crack on my header so i did my own wrenching and pulled off the heads and LTs myself. The plan was to get the crack welded and install header wrap and was looking at TFS 215s until my wife found out the price and put the brakes on that idea. So i started looking at refreshing the valvetrain again and figured that after a valvejob was done they were going to do a clean up mill to ensure flatness so i figured i might as well mill a tad more while im at it. But im at a standstill now because Im torn between refreshing my current heads or purchasing new stg 2.5 heads from TSP and selling my stg 1 ls6s.
Last edited by 427LS7HCI; Feb 7, 2012 at 12:53 AM.
Maybe you can send the heads to AI and get one of their CNC packages for much less than getting new heads
http://www.advancedinduction.com/LSX...inderHeads.php.
http://www.advancedinduction.com/LSX...inderHeads.php.
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OK, makes better sense.
Wives are always a deal breaker, I know, I've had mine 27 years now....
I wouldn't purchase the 2.5s over what you currently have. I'd save my money, butter up the wife, and purchase aftermarket castings down the road.
Purchasing expensive automotive parts RIGHT before Valentines day is a real bad idea...
I know of this personally...
Why does your valve train need a refresh? Did you diagnose actual leakage with a leak-down test?
How old are the heads now? Late model stuff (anyones-not just GM) tends to not wear very much and those heads may need MINIMAL work.
As you're already apart...
I'd pull the heads apart and inspect. You might be able to get away with a hand lapping and not spend money with a machine shop. This will go over FINE with the wife...
A clean up mill is always a good idea but sometimes not mandatory. Milling out 2ccs is fine (I'd go more but then I'd tune as well). If I had a high duration cam I'd be much more careful.
What is your current PTV clearance?
Are you running a big cam?
Now, if you're really serious about getting high end heads then I might re-use what you have now. Not even mill them. Save as much money as I could.
Are the heads straight? Did you use MLS gaskets the first go around?
If so the gasket surface should be cleanable without altering the surface finish much.
Milling out only 2 CCs will not produce a quantifiable increase in output in a LS1 10.5-1 application. Yes power should go up but the amount will be "mouse **** in the ocean". It's not worth the investiment IMO if you can do without the mill job anyway.
If you already have a cam that is big enough to require the compression then I would mill to the optimal point regarding the cam selection. The cam vendor is who I'd listen to regarding optimal static compression ratio.
I'd also rethink the header wrap idea. Wrapping a set INCREASES the chances of header failure issues. You already have 1 crack, do you want to find/create more??? I do believe in ceramic coating or wrapping as it usually increases exhaust velocities and VASTLY reduces engine compartment temps but the wrap (which works better than CC IMO) seems to come with a price of decreased header life....
Many header companies will not warranty a set that has been wrapped.
I'll leave you with a little trick for the wife...
The other night I told my wife of 27 years she was the most "valuable and expensive thing" that I have a license for...
At first she thought it was sweet....
Then later not so much...
Wives are always a deal breaker, I know, I've had mine 27 years now....
I wouldn't purchase the 2.5s over what you currently have. I'd save my money, butter up the wife, and purchase aftermarket castings down the road.
Purchasing expensive automotive parts RIGHT before Valentines day is a real bad idea...
I know of this personally...
Why does your valve train need a refresh? Did you diagnose actual leakage with a leak-down test?
How old are the heads now? Late model stuff (anyones-not just GM) tends to not wear very much and those heads may need MINIMAL work.
As you're already apart...
I'd pull the heads apart and inspect. You might be able to get away with a hand lapping and not spend money with a machine shop. This will go over FINE with the wife...
A clean up mill is always a good idea but sometimes not mandatory. Milling out 2ccs is fine (I'd go more but then I'd tune as well). If I had a high duration cam I'd be much more careful.
What is your current PTV clearance?
Are you running a big cam?
Now, if you're really serious about getting high end heads then I might re-use what you have now. Not even mill them. Save as much money as I could.
Are the heads straight? Did you use MLS gaskets the first go around?
If so the gasket surface should be cleanable without altering the surface finish much.
Milling out only 2 CCs will not produce a quantifiable increase in output in a LS1 10.5-1 application. Yes power should go up but the amount will be "mouse **** in the ocean". It's not worth the investiment IMO if you can do without the mill job anyway.
If you already have a cam that is big enough to require the compression then I would mill to the optimal point regarding the cam selection. The cam vendor is who I'd listen to regarding optimal static compression ratio.
I'd also rethink the header wrap idea. Wrapping a set INCREASES the chances of header failure issues. You already have 1 crack, do you want to find/create more??? I do believe in ceramic coating or wrapping as it usually increases exhaust velocities and VASTLY reduces engine compartment temps but the wrap (which works better than CC IMO) seems to come with a price of decreased header life....
Many header companies will not warranty a set that has been wrapped.
I'll leave you with a little trick for the wife...
The other night I told my wife of 27 years she was the most "valuable and expensive thing" that I have a license for...
At first she thought it was sweet....
Then later not so much...
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Verdad Gallardo OK, makes better sense.
Wives are always a deal breaker, I know, I've had mine 27 years now....
I wouldn't purchase the 2.5s over what you currently have. I'd save my money, butter up the wife, and purchase aftermarket castings down the road.
Purchasing expensive automotive parts RIGHT before Valentines day is a real bad idea...
I know of this personally...
Why does your valve train need a refresh? Did you diagnose actual leakage with a leak-down test?
How old are the heads now? Late model stuff (anyones-not just GM) tends to not wear very much and those heads may need MINIMAL work.
As you're already apart...
I'd pull the heads apart and inspect. You might be able to get away with a hand lapping and not spend money with a machine shop. This will go over FINE with the wife...
A clean up mill is always a good idea but sometimes not mandatory. Milling out 2ccs is fine (I'd go more but then I'd tune as well). If I had a high duration cam I'd be much more careful.
What is your current PTV clearance?
Are you running a big cam?
Now, if you're really serious about getting high end heads then I might re-use what you have now. Not even mill them. Save as much money as I could.
Are the heads straight? Did you use MLS gaskets the first go around?
If so the gasket surface should be cleanable without altering the surface finish much.
Milling out only 2 CCs will not produce a quantifiable increase in output in a LS1 10.5-1 application. Yes power should go up but the amount will be "mouse **** in the ocean". It's not worth the investiment IMO if you can do without the mill job anyway.
If you already have a cam that is big enough to require the compression then I would mill to the optimal point regarding the cam selection. The cam vendor is who I'd listen to regarding optimal static compression ratio.
I'd also rethink the header wrap idea. Wrapping a set INCREASES the chances of header failure issues. You already have 1 crack, do you want to find/create more??? I do believe in ceramic coating or wrapping as it usually increases exhaust velocities and VASTLY reduces engine compartment temps but the wrap (which works better than CC IMO) seems to come with a price of decreased header life....
Many header companies will not warranty a set that has been wrapped.
I'll leave you with a little trick for the wife...
The other night I told my wife of 27 years she was the most "valuable and expensive thing" that I have a license for...
At first she thought it was sweet....
Then later not so much...
Wives are always a deal breaker, I know, I've had mine 27 years now....
I wouldn't purchase the 2.5s over what you currently have. I'd save my money, butter up the wife, and purchase aftermarket castings down the road.
Purchasing expensive automotive parts RIGHT before Valentines day is a real bad idea...
I know of this personally...
Why does your valve train need a refresh? Did you diagnose actual leakage with a leak-down test?
How old are the heads now? Late model stuff (anyones-not just GM) tends to not wear very much and those heads may need MINIMAL work.
As you're already apart...
I'd pull the heads apart and inspect. You might be able to get away with a hand lapping and not spend money with a machine shop. This will go over FINE with the wife...
A clean up mill is always a good idea but sometimes not mandatory. Milling out 2ccs is fine (I'd go more but then I'd tune as well). If I had a high duration cam I'd be much more careful.
What is your current PTV clearance?
Are you running a big cam?
Now, if you're really serious about getting high end heads then I might re-use what you have now. Not even mill them. Save as much money as I could.
Are the heads straight? Did you use MLS gaskets the first go around?
If so the gasket surface should be cleanable without altering the surface finish much.
Milling out only 2 CCs will not produce a quantifiable increase in output in a LS1 10.5-1 application. Yes power should go up but the amount will be "mouse **** in the ocean". It's not worth the investiment IMO if you can do without the mill job anyway.
If you already have a cam that is big enough to require the compression then I would mill to the optimal point regarding the cam selection. The cam vendor is who I'd listen to regarding optimal static compression ratio.
I'd also rethink the header wrap idea. Wrapping a set INCREASES the chances of header failure issues. You already have 1 crack, do you want to find/create more??? I do believe in ceramic coating or wrapping as it usually increases exhaust velocities and VASTLY reduces engine compartment temps but the wrap (which works better than CC IMO) seems to come with a price of decreased header life....
Many header companies will not warranty a set that has been wrapped.
I'll leave you with a little trick for the wife...
The other night I told my wife of 27 years she was the most "valuable and expensive thing" that I have a license for...
At first she thought it was sweet....
Then later not so much...
