How much HP/torque can a stock LS6 (and the the rest of the drive line on a Z06) make before it becomes unreliable? Can it be boosted up above 500 RWHP? 600?
Does anyone have any idea?

Thanks,

Dale

Excellent question! I'm hoping Lee or someone of his technical expertise answers this one! I would like to get 500 to 600 RWHP out of mine someday....but I still want to be able to drive it on the street, too. So at what point does it not become a daily driver and purely a race car?

If I remember correctly I think Lee said that it can take about 500 RWHP before the internals start to get too stressed, and even at those numbers things can still go wrong if you are not careful. Hopefully Lee will come along and either confirm what I am saying or tell me to stop trying to quote him and giving out bad info:)

It's torque that tears a motor apart, so I think on balance the way to look at it the torque, not HP. And from what I have seen a stock LS bottom end can take about 450 RWT without coming apart, but not over 500. The stock LS6 in my vette went for about 2 years with 460 RWT and about 480 RWHP with no problems (Magnusen SCr). I've known half a dozen folks that have the same power one way or another and have had no problems (assuming they don't abuse their cars). But I know of no one who went past 500 RWT or HP that had the engine last more than about 6 months. I also saw one engine where it looks like the block actually split with the boost dialed up to about 12 and 560 RWHP, but a lot more went wrong inside it so no one knows what broke first.
In my experience people who push boost to get 500+ RWHP (7-8 lbs with about 500 RWT at 5500 RPM) break pistons, if they get the same HP with revs instead of boost (heads, cam, around 380 RWT at 7000 RPM), they seem to break the rods. The LS1 (same thing in the bottom end as an LS6, essentially) in our Camaro came apart at somewhere around 540-560 RWHP (425 NA with heads and cam and a 125 shot of NOS) halfway through what would have been a really good 1/4 mile run. It had a broken piston and a bent rod and we never could figure which happened first.
If you rebuild the bottom end of an LS1/6/2 etc., with aftermarket crank, rods, and pistons, its probably good for over 6o0 RWHP. And if you use the iron LS6 block (like the 408 we have int he Camaro now) or the C5R aluminum block (my vette), its just about bulletproof up to 1100 HP, at which point the problem seems to be keeping the heads bolted on.

Boosted? I'm about to undergo a project to exceed 500rwhp on my stock bottom end 346ci N/A!

You can do 500 N/A on 346 easily, but it is not the same as boosted. The low end torque of a supercharged orturbocharged engine is just incredible. A heads and cam 500+ RWHP engine is fun, but has no low end torque: rough idle, little below 3500 RPM, and much less power overall that the same HP out of a N/A Still, don't get me wrong, I love a high reving N/A motor. My advice is to cut no corners on the valve train: shaft mounted rockers from a proven company, good aftermaket pushrods, really good lifters. Our Camaro makes well over 525 RWHP N/A, but then with 408 cubes it should, and there is no magic, just great heads (AFR big port), a big cam (T-Rex +) and lots of tuning. But it is all heavy duty aftermarket stuff and a really high quality top end, which so far has tolerated 7000 RPM with no problems.
Still, on balance, I like cubes, all the best equipment, and boost. My 'vette has 500+ RWT just off idle.That changes completely what a car feels likeon the street.God's own torque curve. Great driving.

ORIGINAL: Lee Willis

You can do 500 N/A on 346 easily, but it is not the same as boosted. The low end torque of a supercharged orturbocharged engine is just incredible. A heads and cam 500+ RWHP engine is fun, but has no low end torque: rough idle, little below 3500 RPM, and much less power overall that the same HP out of a N/A Still, don't get me wrong, I love a high reving N/A motor. My advice is to cut no corners on the valve train: shaft mounted rockers from a proven company, good aftermaket pushrods, really good lifters. Our Camaro makes well over 525 RWHP N/A, but then with 408 cubes it should, and there is no magic, just great heads (AFR big port), a big cam (T-Rex +) and lots of tuning. But it is all heavy duty aftermarket stuff and a really high quality top end, which so far has tolerated 7000 RPM with no problems.
Still, on balance, I like cubes, all the best equipment, and boost. My 'vette has 500+ RWT just off idle.That changes completely what a car feels likeon the street.God's own torque curve. Great driving.
500rwhp easily?Somewhat.On the contrary from what I understand it's all in the setup as to the low end torque.And for the Boosted v/s N/A,what kind of low end tq numbers would a boosted 500rwhp car make? From what I've learned it's better to make the power N/A before you think about power adders.It's got a lot to due with who's tuning it also.I'll be making a pretty good tq curve when I get my car done(I'll beshooting forwhat your 408 is making with my 346!I'm gettin' those TFS heads and a custom cam form Vengeance Racing.500 rwtq at low rpms is awesome! Do you have a graph and did you say that your car was boosted?