C6Z_LS7

My assumption is just based on the number of high mileage 2006 untouched heads I’ve seen still running strong out there. Also, I can’t find the post, but there is also a guy on CF that has a 2006 Z06 used only on the track as well. I can’t find the posts, I’ll look for it. Apparently he worked with GM in the earlier years of the Z06, for track testing.?? Don’t quote me. But I thought I read him stating the earlier 2006 don’t have such a major valve drop issue as later years..

In total, it’s honestly just want I’ve seen and heard. To this day, I haven’t seen a 2006 Z06 dropping a valve but other years. Not to say that there wasn’t, and I agree, there will be guides out of spec on ALL factory heads. That I can be sure of.

Hell, I have an 2006 Z06 and I swapped my factory heads, just to be safe. I wouldn’t chance it. But I wish i had the time and resources to back my conjecture.

answering OP question, my guess, in total Z06s 70-80% left. 30% or less under 30k miles

JABCAT

The info release by GM (though limited) said they started seeing the "machining issue" with 2008s. While I believe them about as far as I can throw them, if you're going to admit to an issue why start with a random model year?

dmuellenberg

Well, I had 100k on my 2006 Z06 when I decided to check the heads, and almost every single guide was out of spec, one so bad it wouldn't even register on the gauge. And mine was completely stock and never tracked. I am just saying if the problem didn't start until after 2006 then they would have had to change something, and AFAIK nothing was changed after 2006. You said you see a high number of high mileage 2006 running strong, but do they know if they have worn guides or not? Just because they are running strong doesn't mean they don't have worn guides. Mine was also running strong at 100k but my guides were pretty much shot, so yeah, my 2006 did have a problem even though it was still running strong so that isn't really an indicator.

jerseydrew

FYI i consider race converted cars to be out of the pool.

666devilcar

LOL, why they are running..... do you take all the salvaged titles out of the "pool" too? If its a track car its modified, so do you take all the mod cars out too? This is a very subjective question that cant be answered . Especially when the rules change.

jerseydrew

Sort of. Full race car and salvaged titles will always have a buyer but it is very niche. Modded corvettes are still considered ok to a point, an h/c/i car is not normally looked down upon as a salvaged title or race car.

let’s be honest this is a figure we’re never going to actually find out. at the end of the day. It’s just a thought experiment

dmuellenberg

It could very well be that there was a machining problem for those years. If that is the case, that just means that the machining issue isn't the only issue that causes excessive guide wear.

dmuellenberg

The question was how many still exists. Race converted ones still exist, don't they?