my c6 Z broke 500whp on the dyno yesterday

[itSSlow98]

ahh makes sense, I wasn't aware of this issue or that people were working their heads to avoid it.

Everyone basically says the day you buy one you should already have the appointment to put new valves in it. When I was considering one I literally had to add $2k to the purchase price to have the heads done the same week I bought the car.

OP is gonna be pleasntly suprised when he gains 60rwhp with a mild cam lol.

 

[SVTORANGE]

Congrats - Sounds good

 

[2004TBV]

Sounds great, congrats.

 

[NA_Cobra]

Probably to avoid the chance of the dropped valve issue on the LS7. Happened to a small # of cars. Machining issue from a supplier. Installing new guides solves the problem but might as well port the heads while their off.

mis-information. it's a design flaw in the LS7 heads and new valve guides does not solve the problem, it's a band-aid.

The only way to solve the issue is to get aftermarket heads as the OP's route.

 

[vettez062002]

mis-information. it's a design flaw in the LS7 heads and new valve guides does not solve the problem, it's a band-aid.

The only way to solve the issue is to get aftermarket heads as the OP's route.

the actual valves are what break because they are hollow/sodium filled. change out the valves and your good. although im still running stock valves lol

 

[Blown02]

Sounds good.
ur numbers are so impressive. 612 hp in a corvette is alot. My car feels so fast at 500hp I couldn't imagine another 100. Im doing a mild cam and calling it a day. Hoping for 540 to 550hp.

ya u will hit that no prob man. keep us posted!

 

[big reg]

mis-information. it's a design flaw in the LS7 heads and new valve guides does not solve the problem, it's a band-aid.

The only way to solve the issue is to get aftermarket heads as the OP's route.

True, but the fact remains Vengeance Racing and WCCH are making a good chunk of change redoing stock heads.

I would go aftermarket castings but the above companies are marketing the replacement guides in stock castings as a fix.

http://vengeanceracing.net/index.php/vengeance-racing-stage-i-ls7-cylinder-head-upgrade.html

 

[Blown02]

HUH? LS7 head design flaw? lets see some evidence.. im always on corvetteforum and havent seen anything like that.theres speculation, but thats all it is just like every other thing they have said could be the prob. ive got wcch st.2 heads w/ the good valves and rockers and have been a few thousand miles and 40+ quarter drags and no prob at all.. theres a ton of people running wcch heads and other ls7 based heads..


sorry OP didnt mean to change subject just wanted to clarify

 

[big reg]

HUH? LS7 head design flaw? lets see some evidence.. im always on corvetteforum and havent seen anything like that.theres speculation, but thats all it is just like every other thing they have said could be the prob. ive got wcch st.2 heads w/ the good valves and rockers and have been a few thousand miles and 40+ quarter drags and no prob at all.. theres a ton of people running wcch heads and other ls7 based heads..


sorry OP didnt mean to change subject just wanted to clarify

Exactly. I let it get to me and lost out on a great deal on a 07 Z in Oct through a buddy of mine at auction.

Valve guide issue is what I have seen after weeks of poking around back then. No confirmation or proof of a "head design flaw". Just Internet speculation by Corvette forum owners. Most reputable shops Katech included have stated the problem as Valve guides wearing and eventually snapping the valve stem causing it to drop.

 

[SVTlove]

i did mine within a few weeks of buying the car. what really sucks for GM guys is the new z/28 has the LS7 and its a badass looking car, but is the problem fixed? most guys say probably not.

 

[SVTlove]

Exactly. I let it get to me and lost out on a great deal on a 07 Z in Oct through a buddy of mine at auction.

Valve guide issue is what I have seen after weeks of poking around back then. No confirmation or proof of a "head design flaw". Just Internet speculation by Corvette forum owners. Most reputable shops Katech included have stated the problem as Valve guides wearing and eventually snapping the valve stem causing it to drop.

HUH? LS7 head design flaw? lets see some evidence.. im always on corvetteforum and havent seen anything like that.theres speculation, but thats all it is just like every other thing they have said could be the prob. ive got wcch st.2 heads w/ the good valves and rockers and have been a few thousand miles and 40+ quarter drags and no prob at all.. theres a ton of people running wcch heads and other ls7 based heads..


sorry OP didnt mean to change subject just wanted to clarify

i did mine within a few weeks of buying the car. what really sucks for GM guys is the new z/28 has the LS7 and its a badass looking car, but is the problem fixed? most guys say probably not.

 

[1969Fastback]

Put a good cam in there and really watch the numbers grow.


My car is still on stock intake, stock throttle body, heads are milled and ported, cam, lt's, CAI, underdrive pulley


Made 605rwhp on motor only... 765rwhp on the 150 shot (nitrous express 90mm plate kit)

 

[1969Fastback]

This was the first pull on the 150 shot, but it was going lean up top, so added a bigger fuel jet

Final result:

 

[vettez062002]

Ugh ok now im ordering heads this week!! I cant stand making 680 anymore...

 

[NA_Cobra]

the actual valves are what break because they are hollow/sodium filled. change out the valves and your good. although im still running stock valves lol

SS valves are band aids. There is no cure other than head swap.

 

[SVTlove]

Put a good cam in there and really watch the numbers grow.


My car is still on stock intake, stock throttle body, heads are milled and ported, cam, lt's, CAI, underdrive pulley


Made 605rwhp on motor only... 765rwhp on the 150 shot (nitrous express 90mm plate kit)

good numbers!!! love the color :beer: love the wheels too!

 

[SVTlove]

This was the first pull on the 150 shot, but it was going lean up top, so added a bigger fuel jet

Final result:

I probably will not be breaking 600whp ever. im doing a mild cam. i don't want to take away its daily drive ability. i dont drive it everyday, but i do drive it a few times a week.

 

[vettez062002]

give complete street performance a call. andrew made me a cam and I was really worried about being able to drive this car and not surge or run like shit. it fires up and idles perfect. has a great sound and its still a car I dont mind taking the wife out to a high class place to eat dinner and not act like a kid. I made 540 cam only and we are pulling my heads off sunday to get ported and milled by AI. shooting for 610whp and 760 on the bottle.

 

[03cobrarocks]

All dees bow ties!

Nice numbers OP!

I need a 2.9 or 3.4 whipple because of all of you! QQ

 

[rdsnk46]

I was waiting for the car to make 500hp then break.......no smokey failure FTW! LOL!