I finally am ready to start my "budget build" that I have been waiting on for a while now. I am looking to replicate the CarCraft article that I found that had very good results: http://www.carcraft.com/techarticles...s/viewall.html

I am totally new to LS motors, I will be using an LQ9 engine that I bought as compared to the LQ4 that they did the article with. Will this be an issue? All I can seem to find is that the pistons are different between the two; so the extra compression from the LQ9 in this case wont be bad thing. I was going to use all of the other parts that they listed, with the exception of GM gaskets instead of FelPro. This will be a carb motor with the GMPP L92 carb intake.

Can anyone chime in as to using the LQ9 will work with this build as opposed to the LQ4?

 

You should be ok, just check ptv clearance with the flat tops of the lq9. Fyi, Holley makes a dual plane intake now for ls3 heads. It's beast and cheaper than the gmpp. I love it

 

I am also wondering if I will have too much compression. Stock LQ9 is 10:1, with the L92 heads, I don't want to be in danger of too much compression for street use.

Wondering if I should dump this LQ9 for an LQ4...

 

Do you plan on running a turbo or blower? If not, keep the LQ9. It's not like you'll be anywhere near the limit of pump gas with the L92 heads.

 

No, I plan to stay NA. No blower or turbos for me on this build. Just trying to get some feedback on other using a similar config. This is a budget build for me and I am reading a lot of mixed reviews on PTV issues with LQ9 and bigger cams because of the flat top pistons.

When I searched I cant find any info on this config. I would also consider going with a less aggressive cam, again, low end power and torque are key for me with this big heavy truck and offroad use that the truck will be used for.

 

If anything I would mill those heads .030 to get even more compression 10 to 1 is low. Ideal would be around 11.0 to 11.5 depending on the cam.

 

If you really wanted, you can run well over 11:1 on pump gas and be safe. There is no piston height differences between an LQ9 or an LQ4. The raised edge around the outside of the LQ4 dished piston is at the exact same height as an LQ9 flat top (which is the area subject to PTV issues). FWIW, I have an LQ9 ( I'm running LS2 pistons with floating rods - same difference) bottom end with LS3 heads, a bit more cam than that one, and have plenty of PTV. You'll be totally fine with that combo on an LQ9. With a carb setup, that combo should run pretty good.

 

That's great news! Glad to hear that it shouldn't be an issue then. So what are these people talking about that are having PTV issues? Huge cams and super high RPM or what?

I am also looking for a cam set up to make more torque earlier on. This is going in a 5000lb+ chevy truck. I emailed CompCam's support and they recommended: 224/234 .581/.598 on a 110 lobe separation

Again, totally new to engine building and LS's.

 

I just built this same motor in my silverado but used LS3 heads, I have 1500 miles on motor and ruined it with sand and TBH im not mad at all because I was disappointed in the build. Dont get me wrong it has tons of power but would guess only 380 HP to rear wheels and wasn't all it was to be when I built it. I used LQ4 but changed to mahle pistons which are flat tops and CR was 10.2:1.

A member on here or performance trucks told me to go 12:1 and I didn't take his advice as tuner said thats to much and while I rebuild it now thats what im going to do. I built mine on the idea of not getting a stall and even with the way I set it up I ended up putting a stall in. These heads lose alot of low end torque which is needed for your heavy truck. Most also say that you need to use them on more cubes as in a stroker.

If you would put this motor into a car it would be a beast however in a truck its not a good set up unless you get a good cam and stall.

 

What was disappointing about it? I am trying to go for more cubes but a 408 stroker isn't really in the cards right now. I feel like I really need an LSx454 to move this truck. I just don't see the torque numbers from these 6.0/6.2 LS engines...

 

Note what he said in post #18, then this.


https://ls1tech.com/forums/generatio...mbo-build.html

With a carb'd manifold, I would look at using a custom cam from one of our vendors. It's kind of hard to not make power on an LS3 headed 6.0 with the right cam setup.

 

My cam was speced by geoff and approved by PatG for my set up. Dont get me wrong this thing has power up top but down low with mud tires and lift it lacks TQ. Even with 5.13 gears and 3600 stall. This set up I can see would be a beast in car or lowered truck but for lifted truck its not what I think it could be with a 408.

 

Check out the engine that newschool72 built for his 72 Camaro. It uses the GMPP dual plane intake and a custom cam. It makes excellent power and torque.

 

I got 374/370 out of my lq9 with l92 heads. I used a small ls6 cam and never touched the spark tables during tuning. Pretty sure it had 400 in it. Now ive swapped in a cammotion cam and expect 430-up after tuning. I used an lq9 and rebuilt it with new 4.030 pistons, so 370ci.

 

NuckenFuts cam is 222/230 112+3 and he just indicated that his 4x4 truck is too soft on the bottom, even with a 3600 stall. That is some very good, applicable data to contemplate and apply to your truck build.

With 5000+ LBS to get moving, I wouldn't use a single plane intake for your application at all. I would be looking at staying with the stock L92 fuel injection truck intake or if you intend to use a carb, the L92 Dual plane intake from GMPP or Holley would be a better choice.

Remember, you are at least 1500-2000lbs heavier than most of the cars on these sites. Beware the temptation to just follow a magazine build or someones drag combo that is fast in a 2800lb car. You will need to have a ton of low and midrange tq to make that truck feel snappy.

LS3 heads are easy to overcam. Go over-large it and it will be a disappointing and expensive lesson. I would be looking at a custom cam between 210 to 220 range on the intake, but would surely speak to and defer to one of the cam experts from CamMotion, Bullet, Tick, EPS, ect. Be very specific on your goals and drivers seat expectations. You need to identify what low speed, part throttle characteristics and the compromises you are prepared to make.

Delay swiping the credit card and instead spend some quality time reading and on the phone compiling some specific education regarding your application.

Though I cautioned following magazine buildups, this is is a good read on a lq9/ls3. http://www.hotrod.com/techarticles/e...2/viewall.html.
It's old info from '07, and there are surely refinements that could be made with more modern grinds, lobe profiles, LSA, ICL, ect, but, the article provides some pertinent data.
- Notice how the small 210/218 cam clearly dominates the other cams up to 5200rpm.

Or...look up Stock48 on this forum and have him help you build a small cam turbo 6.0 combo and it will surely not disappoint at any RPM!