BFB2000

Hey guys, ok so I have a 2000 gmc with an lm7 in it. I have done NOTHING to it thus far. However, what im looking at is an ls6 cam, headers (shortubes more than likely) and after that i'm not sure. I'm not huge into frankenmotors, however they do not scare me. I know the ls6 cam is a sound start. Might get a set of heads to have ported and polished, and pretty sure i'm going to get a programmer (advice on brands?). I would like to make 400 to 450 horse as i have buddys with new badass trucks (SVT Raptor, and HO Ram 1500), that i used to just beat the **** out of with the same stock truck i drive now when they had lesser trucks. I need to keep up with these guys badly. If it matters i have the trailering package so i have the 3.77 rear end so that's already taken care of and i am going to be having the trans rebuilt with a shift kit. The track also does have almost 300,000 miles on it and i am not afraid of replacing internals for some reliability. truck is my dd too in the oilfield. But it just cruises all day. So reliability is a must if suggestions are frankenparts. Thanks

Paul57

I think it will be a little cheaper for you if you find a 6.0 LQ4 or LQ9 from a 3/4 ton truck, van, Escalade or Silverado SS. The LQ9 has flat top pistons for a little more compression but they are harder to find. If you want to beat up on the other trucks and you aren't running the 1/4 mile be sure to build for Torque and don't worry about horsepower so much. Put in a Top Shelf brand of heads if you can afford it and that will build you the most power in your operating range...AFR, PRC or Trickflow in the 210cc to 215cc category. Torque and Traction win on the street.

BFB2000

Thanks I have considered that I just like the revs from the lm7.

Paul57

Sorry about that...I missed the part that said LS6 "cam". In that case, get the Trick Flow 205 or AFR 210 heads if you can swing it. They will make the most power and give you the best MPG's for a daily driver. A custom cam will give you the best results and only costs another $25 (typically). Talk to Patrick G or EPS... https://ls1tech.com/forums/generatio...am-change.html , http://www.engpwrsys.com/

BFB2000

Thanks that gave me some numbers to go by if I decide that porting and polishing stokers would work better... Thanks. I've heard that lq4/9 heads can be used but youd have to have them milled down to keep compression, any knowledge?

BFB2000

do you know any thing about the ls6 cam swap? do I use the yellow or blue stripe valve springs?

Burken01

iTrader: (88)

Blue springs were for 2001 ls6 camshafts
Yellow for 2002-2004 ls6 camshafts

I'm pretty sure that's right, unless the colors change over the years

Which ls6 cam do you have?

BFB2000

i haven't gotten one yet. I just want to know if there is enough of a difference between the springs to matter. Im pretty sure i'm just going to buy the chevy performance one off of summit racing

Paul57

Have you taken a look at other cams?? A 5.3 really handicaps your low end torque potential which is what a truck needs the most. I think one of these would, most likely, work better for you... http://www.vincihiperformance.com/ca...s%20truck.html

Paul57

243 heads have more compression (smaller chambers) than 317s (LQ4, LQ9).

BFB2000

Right I know that. As for the total motor swap, im pretty sure about sticking with the lm7 I just love this truck. yes, I know im losing the possibility for a holeshot hero but I just would rather have a rev monster with the trans rebuild and programmer I should be able to grab for the power still anyways.

Paul57

If your power is too far up into the RPM range you are going to need a bigger stall too.

TheWolfMatt

Had to sub the thread as I'm doing about the same thing with my LM7 in my 01 Silverado Z71. Nice to see that you're still running yours hard at 300k.

BFB2000

yeah the motor has outlasted about to be 2 trans'

TheWolfMatt

Glad I'm not the only one who's had trans issues in that truck. I've gone through 3 now and am working on a new rebuild for a monster 4l60e for the next one that goes out, only a matter of time.

gagliano7

What makes you think the 6.0 can't rev? You would be better of going with a 6.0 more torque and it will rev just as good as a 5.3. i used to shift my 6.0 gto at 6500 power shifting.Baby loved to rev.

BFB2000

i understand that after building a lq4/9 that the rev reliability would be there. but i have taken this bone stock lm7 to 5500 hundreds of times. and im not planning of putting all the power between 4500 and 6000 either. you can built these with a certain amount of low end power too. i'm planning on upping the compression a bit too to and some low end grunt. a programmer would add me a bit more fuel. i am looking at different options for intakes to get air moving. and like i said i have a 3.77 rear end so it doesn't fall on its face either (unless the trans forgets to shift into first on the takeoff).

wolf matt... do you take your z71 up to 5500revs a lot? i do quite a few times and i wonder if the trans plates are built to take the high revs of the motor. shift kits and upping line pressure with a programmer will definitely solve the problem.

TheWolfMatt

Yes, I get it upwards of 5500-5800 almost on a daily basis and it runs just fine. It does smoke every so often but very minor. But then, what can I expect with over 210k on the truck. I also have the 3.77 gears in the back end and I find that all the extra low end grunt is a bit mutch on traction, doesn't bother me to use the AWD the truck has, picks up and goes like a whipped horse in AWD.

mark21742

I spin my 408 up to 8,000

You might take a look at something like a 224/230, just at or under .600" lift on a 110-112lsa cam instead of the ls6 cam....I think you'd like the powerband.
Also a good 2,600-3,000 stall will really wake your truck up.

As for tuning, find a few friends with GM cars to go in with you and buy Hptuners...$650 for it, bit as is you can tune up to 4 cars/trucks till you need to spend any more money to buy more credits, and this software is on a completely different level than a hand held tuner.

BFB2000

I take that in consideration mark. I actually started broadening my search and found that lingefelter has a cam with the same specs as above. and it comes in a package with springs too.just a 150 more than a stock ls6 cam on summit.