Chicago Crew UnderBoss

iTrader: (1)

My z06 has stainless werks full tube headers, x-pipe, Halltech cobra, air intake, x-pipe and dyno tuning and through the 4.10 gears makes around 380rwhp. If i were to just swap out the heads to Patriot stage II LS6 head what rwhp do you think i would pick up? I figure maybe only 10 for just the head swap.

JF WS6

I'd say like 15 or so, but if you're going to do that - when you have the heads off I'd just go ahead and upgrade to 1.8 roller rockers so you can get a little more lift out of the LS6 cam. You'd definately be over 400RWHP I'd think.

Cal

iTrader: (1)

A lot of people get 20 hp+ from stage II heads with a 224 cam already in place. Might as well do a cam upgrade while you have the heads off.

Chicago Crew UnderBoss

iTrader: (1)

CAL,

I've gone so extreme with my 98 C5 with its 427 MTI C5R motor that i really don't want to open up my brand new LS6 engine with a heart transplant so early on in the game as this car needs to remain 100% reliable and i have broken valve springs before with a cam and just can't stomach a broken one when i am taking a cross country vacation road trip with the Z06 with the wife (if you know what i mean).

I couldn't agree with you more that a cam swap is the best way to really WAKE UP these LSx motors but unfortunately in my mind at least, stock reliability goes out the window when opening up the motor and swapping cams, etc. That's why i am better off going a bit more conservatie with a possible head and roller rocker swap and still retain stock idle, etc. and hopefully great reliability for my 03 Z06, especially since i have gone so nice and EXTREME with my 98 A4 vette

SouthFL.02.SS

So swapping heads is a better idea?
A correctly done cam swap should be rather reliable.

Chicago Crew UnderBoss

iTrader: (1)

In my mind swapping heads seems to be a less intrusive mod to an otherwise stock LS6 motor than swapping cams, especially when it comes to breakin valve springs with a high lift cam and idle quality, etc.

What i really need to do is just relax and keep the motor stock for now and when the warranty is over consider throwing on some twin turbos on the Z06!

SouthFL.02.SS

Otherwise stock [SUPERSTROKER 427ci] LS6 motor?
Am I missing something here?

99 Black Bird T/A

iTrader: (4)

LPE's CNC'd ported LS6 heads sold thru GMPP gained 29rwhp on a Z06 with supporting bolt on's and LS6 cam according to SPDC about a year ago. I would expect a quality set of ported LS6 heads to gain about the same over stock LS6 heads.

With that said, I would suggest checking out TEA's new Judson signature 2.5 LS6 head. You could swap out and sent your heads back as cores. While they will cost a little more than the Pats, you'll get a head with an intake port, chamber; valve job based on what SAM has learned about LS1's. SAM seems to have an excellent edge over almost everyone on LS1/LS6 engines. It’s well worth a call to TEA to speak with Brian before deciding. I think this would have the most potential to get you the best gain for your set up at the current time. TEA also has an excellent history to high quality parts that don’t break or tear your engine up. The TEA 2 year/24,000 mile valve train warranty offers extra assurance in my opinion over almost all other set ups.

With a Z06 that came with factory LS6 heads personally I'd want to keep that 243 casting number on the heads instead of a set of 318 LQ4/9's machined to LS6 specs then ported. Nothing against Pat on this, I think they make an excellent product and I strongly considered getting a set of their LS6 style heads for my 91 RS. Some die-hard typical Corvette enthusiast will probably ask how can it be a real Z06 without real Z06/LS6 heads? Of course it is your car and as long as your happy with the set up that’s all that really matters.

If you go with Pat you can save a few dollars on the port work and sell your stock LS6 castings to keep costs down. I think the Pats will show 25+ rwhp gain and more with more aggressive cam like a stock mannered LPE GT2-3. If you decide to go for the Pat’s please PM me as I have a friend planning an engine build up. He might be seriously interested in your LS6 cores and sending them to TEA for their new 2.5 Stage 2 Judson Sig port work.

As always just .02 worth.

Chicago Crew UnderBoss

iTrader: (1)

Not sure but to clarify i have two vettes and the MTI 427 C5R LS6 headed motor is in my 98 A4 C5 Roadster and the 100% stock LS6 motor is in my 50th anniversay 03 Z06! This post refers to the the stock LS6 motor in my Z06 which right now has aggressive bolts on mods including 4:10s!

SouthFL.02.SS

Ah, totally clears things up.
Even MORE reason to go with cam only.

SouthFL.02.SS

Even better; Stealth Cam + abovementioned TEA 2.5 heads w/ dual springs...

Chicago Crew UnderBoss

iTrader: (1)

YEah, i agree with you that to get the extra 40 to 50HP i am really looking to get out of the stock LS6 motor, that the cam only swap is the call, but i am just relucant right now while Z is under full warranty to open up that stock LS6 motor and doing the cam swap which will not only void my 3 year warranty, but will make the motor in my mind not as reliable as it is now concerning valve springs breaking, etc. Will sleep on this one and decide on way or the other over the winter.

THanks man!

Jason 98 TA

iTrader: (4)

I haven't got to install the new heads on a car with ls6 heads already, but I would assume 20rwhp pretty easy. Combine that with the fact that the heads retail for 1795, then you could sell your factory heads for 900 or so, leaving you only spending 895 for ported stage 2 heads with big valves & springs & retainers good to 650 lift! (incase you go big cam)

Jason

Cal

iTrader: (1)

I understand your concern for reliability and broken springs. One thing I like about the Thunder Racing cams is they have a bit less lift than some of the others, which should make the springs last better. Another thing is to use good quality springs and always get the engine up to full operating temp before reving it too high. Stiff springs are brittle when cold.