Dansic

I recently bought a 2009 Pontiac G8 Gt with the 6.0 L76 in it. It's automatic, so what ever I decide to do will revolve around NOT destroying the 6L80 in this thing. I want to TRY and get 500 rear wheel horse power naturally aspired or better. An LS holding 6L of displacement should do this just fine; its just I'm on a budget. The only thing I have is time and consistent savings (USMC is good for that). I compiled a parts list of what I think is a good starting point for this goal. I'm trying to avoid breaking into the short block and going crazy with fuel/air parts. I'm looking into a 3.27LSD from a Camaro if that helps any too. Let me know what you think, what you would change, add or leave out. (Summit Racing Parts #s) Thanks!

NAL-12629051 HEADS BARE
MAN-11620-8 INTAKE VALVES
MAN-11621-8 EXHAUST VALVES
CCA-26926TS-KIT VALVE SPRINGS/RETAINER KIT
CCA-54-469-11 CAMSHAFT
CCA-7106 TIMING CHAIN
CCA-875-16 LIFTERS
CCA-7955-16 PUSH RODS
CCA-1675-16 ROCKER ARMS
NAL-12595365 LIFTER GUIDES
TFS-30675540 TIMING CHAIN DAMPENER
ARP-234-4317 HEAD STUDS
FEL-HS26192PT HEAD GASKET KIT
NAL-12589016 CAM RETAINER
NAL-12570471 VALLEY COVER
NAL-12594779 PCV HOSE
NAL-12579145 VACUUM CAP
SUM-G1485B PIPE PLUGS
TCI-242976 TORQUE CONVERTER

DavidBoren

For those that may be curious, the cam listed is 231/247 @ .050, 113 lsa, 617/624 lift.
The heads are 260cc ls3 heads with 70cc combustion chambers.
It's a 3100rpm stall tci 10" converter.

redtan

iTrader: (5)

Why the big heavy SS valves when the GMPP LS3 heads come with nice hollow stems?

Dansic

I'm still learning, it's why I asked for the constructive criticism before I started buying anything. The valves were a choice based of off prior experience. Never used hollow valves before, and my spring choice has a 505lb rate for the aggressive cam profile, figured it would pick up a little valve weight... I understand that hollow valves reduce weight by 10%, but are they just as reliable? If so, I can just get the NAL-88958758 heads instead. Anything else come out as odd??

DavidBoren

Forgive me, I just don't have time to go back to summit to look up the pipe plugs you have listed... Are they plugs for the rear steam vents on the heads? If so, get the crossover, or four corner venting, plugging them is just lazy.

Dansic

DavidBoren, actually they are for the oil passages that supplied the DoD/AFM lifters. I know the valley cover plugs them with o-rings, but I'm paranoid and a few people have suggested to me that I plug them with those.

DavidBoren

Ok, got it.

redtan

iTrader: (5)

With better lobes and less aggressive springs you can do fine with the hollow valves.

Me personally, I'd rather do a soft lobe, medium spring and hollow valves over an aggressive lobe, high pressure springs and heavy stainless valves. Much better valve control and will allow you to rev more and make more power.

Given the fact that you want 500rwhp out of the 6.0 with GM style heads, you're going to need to make good power up top. Good power up top comes with excellent valve control at high revs, which will be hard with your combo and much easier with a light valvetrain.

DavidBoren

Unless it comes at the expense of durability, less moving mass is always better. And in the case of the hollow stem valves, durability is not compromised, at least at the levels of the wet sump oiling system limits, so it's a win-win.

flintwrench69

iTrader: (11)

I just bought the valley cover, no problems!

Dansic

If I can run a less aggressive cam I will. My goal is 500 rear wheel horse power though. So something with less over lap and less duration. So lets say I choose a cam with 222/224 @ .05 .588/.601 lift w/ 1.8r, and 112 centerline. Thats overlap from 13o down to 1o... My spring rate for this cam is down to 408lbs as well. I've changed my head choice to the GMPP CNCed 276cc/68 chamber. Those heads come with the hollow valves. This would def make it easier to run pump gas... Any other ideas??
Also flintwrench69, glad to hear you haven't had pressure problems. I'm just a paranoid mess with it though. Lost a couple engines to internal pressure loss. (my fault for not watching gauges)

redtan

iTrader: (5)

Softer lobes does not necessarily mean a less aggresive cam in terms of duration and overlap. And also, a small duration cam with less overlap does not necessarily mean it's a softer cam.

A big *** 240s cam can have decent lobes and be easier on the valvetrain and more stable than a baby cam in the 220s. It's all in the lobes, and that's where I mentioned the softer cam.

The 222/224 cam is awful choice for making that kind of power with rectangular port heads. You need something bigger and with a wider split.

DavidBoren

I think the cnc hollow stem heads with the smaller combustion chamber is a good choice.

And sir, unless it's a matter of pride or preference, please just get a custom grind cam. Call kip at cam motion. I always say to call cam motion because they have really good lobe profiles and excellent core materials, and I have never heard anything but good things about their customer service.

But any of the vendors on this site can set you straight with what you need.

KW Baraka

iTrader: (7)

Why?

What exactly are you looking to do with the car?

I ask because there may be other ways to get what you want aside from hitting 500 rwhp......unless you're just chasing the number.

KW

Dansic

Now I feel like I just need to study cam profile articles.... Your referring to acceleration off the base circle and up the flank when you say softer right? I can play around with numbers all I want in the LSA and duration, but the larger LSA and duration I go the further out of the street-able range I go. Just what kinda of cam do you suggest I go for assuming I have the 276cc/68cc hollow stem heads? Disregard street-ability for now, just hit me with dur/lsa. I have read of a few people gaining close to 500 with cams in the 22x range, but no details. Could be full of ****. IDK

KW Baraka the goal is more of a "can I do it?" and if I can I will. But from what I'm gaining from this thread is that my power range will be to far up the RPM range to be worth crap on the street. Lowering the HP number isn't my mantra, but my end goal is max potential from heads, intake, valve train mods. The car is a weekend toy for the street/strip. And there are a couple of other ppl around my command that have G8s and I wanna be faster

DavidBoren I'll give them a call and see what they can do for me once I figure a little more about what I really need. All my free time has been tech articles past few days.... This **** is harder to work out than a V22 hyd system...

Dyno Junkie

Our LS3 doesn't make anywhere near 500rwhp, but it has pushed a 3,890lb Monaro to 11.08 and also 122.78 mph in the quarter.

Comp Cam 231 239 .617" .624" 113.

DavidBoren

There's a ls2 in the dyno results section making 490 sae corrected rwhp with nothing more than a set of tea stage two 243's, a msd intake, and a 236/242 on 111 ed curtis cam.

So getting 500rwhp, or at least very close to, with a relatively simple six liter is perfectly possible.

redtan

iTrader: (5)

And a guy with the same GMPP LS3 heads and a similar cam to the OP made 453rwhp in a GTO also.

500rwhp in a 6 liter ain't exactly a walk in the park...you need good components in the intake manifold, heads and cam.

DavidBoren

Maybe the ls3 heads aren't the answer, then. The OP is asking for feedback on a proposed parts list for building his 6.0 to 500rwhp. I simply directed him to the ls2 in the dyno results section. It also has a parts list of what was used to achieve damn near exactly what the OP is looking for.

Maybe instead of the ls3 heads from summit, the OP should be looking at stage two 243's from TEA.

All I'm saying is that if the OP has a six liter and wants feedback on a parts list to get him to 500rwhp... right now there is a 490rwhp six liter with an accompanying parts list in the dyno results section of this website/forum.

So if 500rwhp isn't a walk in the park and requires good parts, then the OP should probably look at the exact parts that yielded the exact results he is looking for.

redtan

iTrader: (5)

To be fair, that one specific model is a little bit on the high side. Not saying it's not true, but most ported 243 headed LS2s with a medium-high cam are in and around the 475rwhp mark. To be realistic in that goal, you'd need a little more compression and a better head to do it.