Living with a bone stock LS7
#41
Pro
I seem to be in the same boat here.. had a 996 911 Gemballa 650 was a monster of a porsche.. got rid of it and years later gave the z06 a try... Liked it so much I ended up getting a backup..
From the factory the Z is VERY capable, a few upgrades and you have a full blown race car, and in factory trim it handles like it. I pulled the heads on both and sent them off immediately.. went all factory parts and plan on "servicing" them after a few seasons of track time.. PASAGEMAKER with 6! NICE!!
From the factory the Z is VERY capable, a few upgrades and you have a full blown race car, and in factory trim it handles like it. I pulled the heads on both and sent them off immediately.. went all factory parts and plan on "servicing" them after a few seasons of track time.. PASAGEMAKER with 6! NICE!!
Find me at the August Indy Airstrip Attack with my RPM Stage 4 2008 VR Z. Has a FL Marine Corps Plate that says C8Z06. Intended to buy one but 720 engine horsepower and less than 3100 pounds curb weight with my 18 inch Forgelines, CF hood etc., I decided to wait on the C8. My HP to weight ratio works out to under 4.3 pounds vs 5.5 for the C8Z. Gotta love a C6 Z06.
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#42
Racer
I watched a very interesting video from a well known Corvette shop owner. He said 2 things. Don't modify your engines and secondly rev up to 6500 rpm only. You are not getting much in top 500 so why stress it. That way you will never have head problems. Also following this subject for many years, the ones with head problems are most of the time if not all who have modified their engines. That is my impression.
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#43
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The idea of 6k vs 6.5k vs 7k rpms and guide wear is nit that applicable to me the way mostuse their vehicles. Will a higher lift cam with aggressive lobe profiles cause more guide wear... yes absolutely but I think the 500-1k rpm difference being debated here in relation to guide wear is negligible when we are talking about for most here quick freeway on ramp revs. Now sustained 6500rpm+ rpms say for extended periods of time (like in am offshore poweboat applicstion, etc...) sure but for most this is just not the case when flirting over 6k rpms
Just my opinion of what I have seen real world street, dyno, spin tron and track testing
https://americanheritageperformance.com/
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The Fastest N/A C6z06 in the world is running AHP Ported Cylinder Heads (C6z06 N/A World Record Holder in 1/4 Mile 9.187s @ 152.41mph)
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The Fastest N/A C6z06 in the world is running AHP Ported Cylinder Heads (C6z06 N/A World Record Holder in 1/4 Mile 9.187s @ 152.41mph)
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#44
Drifting
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2023 Corvette of the Year Finalist - Unmodified
2022 C6 of the Year Winner - Unmodified
pretty much the same...I went with AHP pkg 4 at 10,000km (6200miles) for peace of mind as soon as I bought my car. It was 10yrs old at the time and my local Porsche guru did the swap (didn't know anyone local in the LS world yet). Labour cost CAD$1800 (about USD1300).
These were the "wiggle test" results on my original heads (with valve springs removed)...and, yes, I know wiggle tests are no longer deemed acceptable by the sages. I was told any measurement over .008" is considered 'out-of-spec', and, if I recall, AHP specs .005 on their reworked heads as measured with a dial gauge.
Cyl 1
Int- .008"
Exh- .005"
Cyl 3
Int- .008"
Exh- .005"
Cyl 5
Int- .009"
Exh- .006"
Cyl 7
Int- .007"
Exh- .005"
Cyl 2
Int- .010"
Exh- .007"
Cyl 4
Int- .008"
Exh- .006"
Cyl 6
Int- .010"
Exh- .006"
Cyl 8
Int- .009"
Exh- .007"
So, several guides were borderline and some just a little over.
I do track the car a little, but kept the engine stock for reliability and longevity...its fast enough for me, and I can always try driving it better. Anyway, mostly just a cruiser that is meticulously maintained and treated very gently and lovingly.
So...the question is, would the stock heads have lasted? would there have been issues? I'll never know. But at least I've mitigated risk and feel ,much better about that.
I'll add that unlike many, I've also done what I can to reduce high temps on track, which surely don't help with overall engine wear anyway, and I also avoid lugging the car in 6th (ebb/flow of traffic), or loading the engine at low rpm in taller gears...which is easy to do with such a torquey car, but I feel may also introduce some undesirable harmonics which may also exacerbate some other issues noted with these cars.
Anyway, sure, there may be a lot of internet/forum hype, and I personally know people with high mileage untouched LS7s, as well as others with modded engines that have become 'maintenance items'...even used on street. But, unlike some other areas that I regret having blown $$$, I have no 2nd thoughts about having 'fixed' the heads and would do it all over again, the same way.
To each his/her own
These were the "wiggle test" results on my original heads (with valve springs removed)...and, yes, I know wiggle tests are no longer deemed acceptable by the sages. I was told any measurement over .008" is considered 'out-of-spec', and, if I recall, AHP specs .005 on their reworked heads as measured with a dial gauge.
Cyl 1
Int- .008"
Exh- .005"
Cyl 3
Int- .008"
Exh- .005"
Cyl 5
Int- .009"
Exh- .006"
Cyl 7
Int- .007"
Exh- .005"
Cyl 2
Int- .010"
Exh- .007"
Cyl 4
Int- .008"
Exh- .006"
Cyl 6
Int- .010"
Exh- .006"
Cyl 8
Int- .009"
Exh- .007"
So, several guides were borderline and some just a little over.
I do track the car a little, but kept the engine stock for reliability and longevity...its fast enough for me, and I can always try driving it better. Anyway, mostly just a cruiser that is meticulously maintained and treated very gently and lovingly.
So...the question is, would the stock heads have lasted? would there have been issues? I'll never know. But at least I've mitigated risk and feel ,much better about that.
I'll add that unlike many, I've also done what I can to reduce high temps on track, which surely don't help with overall engine wear anyway, and I also avoid lugging the car in 6th (ebb/flow of traffic), or loading the engine at low rpm in taller gears...which is easy to do with such a torquey car, but I feel may also introduce some undesirable harmonics which may also exacerbate some other issues noted with these cars.
Anyway, sure, there may be a lot of internet/forum hype, and I personally know people with high mileage untouched LS7s, as well as others with modded engines that have become 'maintenance items'...even used on street. But, unlike some other areas that I regret having blown $$$, I have no 2nd thoughts about having 'fixed' the heads and would do it all over again, the same way.
To each his/her own
Pretty happy and guess I'm treating my LS7 properly, like a race engine and with the respect it deserves. BTW, this analysis has about 900km of track use, often tickling the rev limiter. My engine is always properly warmed to operating temp (i even use a warming blanket on the oil tank for cold starts), and no lugging/load.
Again, my engine is 100% stock, just has a good custom tune (about +30whp gain, part of which is surely the nice AHP head work).
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