Bigbrake

Mine is a 2012, so it has the revised exhaust valves and it has just 13k on it now- it is stock. I was curious so I took a look this winter- The exhaust guides all check within spec as of this last winter, under .003 but just barely. The intakes are another story and this is one reason for the accelerated wear, the titanium valve coating is a problem, Del west advised Gm that the coating is insufficient but they did what they wanted right up to the end of production (just a few years ago in crate form and 2015 for the Z28) the intake guides all have .006 or more of play right now, one has .012- #5 The coating on the intake valves gets rough and can saw their way thru the guides in short order. Returning a stock intake valve even after tumbling and polishing is asking for more problems. Katech has a nice ti moly valve that goes good with bronze guides, keeps the light weight and ditches the problem with the stock coatings. And as far as Stainless valves, yes they weight more but are more durable and don`t eat the guides by themselves BUT you do have to account for them with better springs more valvetrain hardware that is up to the task of controlling the extra weight. I`m going aftermarket castings, Tony Mamo trick flows, his roller rockers- basically sidestepping all these LS7 head issues at once

Bertram65

Who checked it?

passagemaker43

I concur with the bad news travels fastest. Check my older posts. At one point I added up all the C6 Z06's my hard driving (many of us) group put on their stock Z06's. Memory tells me it was 14 or 15 cars with a total of close to 400,000 miles. No issues. Several ultimately had the heads pulled when they modified them and were in factory spec. We had almost all years except for 2012 I think. Doesn't men there is no issue but only there are many variables to consider. For Example none of the cars were horsepowered up without doing the heads, mostly older drivers though still being pushed fairly hard, No cams with much over net .650 lift, no one making a habit of hitting the rev limiter, etc. Not trying to make a policy statement but just relaying one groups experience.
For my part I think no performance minded naturally aspirated fan should miss out on owning an incredible car. I know the C7 guys will hate this but no comparison. I really liked my C7 Z06/Z07 but sold it because I wasn't a good fit. I like more edge and lighter weight. 3100 something pounds vs 3500 something? Give up 400 pounds of weight? Not this guy. Add to that a weenie supercharger that excels at bottom end spinning tires but lacks even the capacity of the C6 ZR1 supercharger (1.7 litres vs 2.3 litres) for top end pull. Just my biases.

By the way i currently own 6 C6 Z06's with 4 of them still stock with respect to the heads (one is a supercharged Callaway). Total of 117,000 miles on the 4 stock ones. Years are 2009, 2010, and 2 2011's.

Either way as someone said, do what makes you comfortable.

CliffyDeuce

Look at Able Chevrolet in Rio Vista. It's been several years since I lived in NorCal, but they checked my heads and got both of them replaced under warranty. They had guys that tracked their Corvettes and were very familiar with the potential issue. They treated me well, and they wouldn't be that far for you to go.

smw_zo6

Thanks, I heard them mentioned several years ago but at the time I had my C5 Z06 and didn't think about it further.

Too-Fast

I own a 2011 Z07 since new, at approx 2500 miles I performed the wiggle test, too much movement for my comfort. All guides verified out of spec, new AHP Package 4 heads.

iw172

60k+ miles on mine ZERO issues. very little oil consumption between changes, great oil pressure and no noise. best car I’ve ever owned and I drive in all over the country. 13k miles when I bought it in ‘17…

449er

We here on this forum are but a small percentage of LS7 owners out there in car land, we all have read of the catastrophic engine failures on these engines but the real question is....how many LS7 engines really did grenade themselves over the years? Is it 2%, 5%, 10% or ? There are many people out there driving their LS7 cars with no idea that there may be an issue with their engines. No one knows if it's not as bad or worse than the forum comments here. I recently attended an All Chevy car show & walked up to a ZO6 owner & asked him if he had his heads "fixed", he looked at me like I was from Mars

gmansbu

I too wanted to retain stock drivability. At the same time I didn’t want to worry about the heads all the time. I went with the AHP package 4 heads a couple months ago. I couldn’t be happier and it’s nice having the piece of mind. My Z had 9k miles on it when I swapped heads.

tommyc6z06

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

2500 hd

I can't decide whether to have mine fixed, just drive it like it is, or trade it for something else.

dmuellenberg

And exactly how do you know you have ZERO issues? If your guides are out of spec, that is still an issue. I had 100k on my Z06, no oil consumption issues, no excessive noise, good oil pressure, etc. but I had the guides checked and almost every one was out of spec, a time bomb waiting to happen. Unless you have checked your guides, you don't know if you have an issue or not.

Bertram65

The worst would be having your LS7 "fixed" and then having issues as a result of the work to fix it, there are a number of stories on here about that happening.

92rsz

Ignorance is bliss until it isn't. I'd pull a valve cover and check at the very least. My ls7 had every exhaust valve way out of spec at 18k miles

2500 hd

I'm sick of thinking about it; I'm probably going to trade mine in on something else.

gmansbu

This is the third c6 z06 I have owned. There is a reason I keep coming back to it - it’s a special car. I had a 997 911 Turbo before this. Sold that 6 months ago when I bought my current Z. The 911 was wonderful but still wasn’t the c6 z06. In my opinion there are no other cars at this price point that get me excited like the c6 z06 does.



In a world of electric cars and forced induction our z’s are becoming dinosaurs. 6 speed manual performance cars are also becoming a thing of the past.



At the same time being my third z06 I knew what I was getting into. I knew I had to have the heads done as soon as I bought the car. I’ve also accepted I’ll be taking the heads off every year or two to check how the heads are doing and address if necessary. It’s a small price to pay to own something this special.

American Heritage

For sure fix the LS7 heads
No need to cost yourself $20,000 plus thousand dollars bc you did not fix the stock LS7 heads.
Just had a customer from Europe email me saying he purchased a very low mileage (3,000 miles) c6z06 that had never been abused or even driven hard... Two weeks later he emailed me saying he dropped a valve and destroyed his entire engine bc he never addressed the stock LS7 head issue. Now he is going with one of our fully forged 700+hp 442ci LS7 builds.
Just fruit for thought
here is a link to our package 4 LS7 head rework which is the most trusted and proven LS7 head fix there is:
https://americanheritageperformance....cylinder-heads

dmuellenberg

But, but it's all just internet hype!

wjnjr

Good idea. Do it, take the plunge and make a decision. You will be glad you did.

The road of life is paved with flat squirrels who couldn't make up their minds.

KennyPowers

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!!