Camshaft help

[askkmb]

Hey, im building and LQ9(6.0) wit L92(6.2) and now im not sure which cam to put in. Does the 6.2 cam fit in the 6.0? If it does, which one would you recommend???
Thanks, Beto.

[CHEVELLE of JONESY]

I believe all LS cams have the same journal size.
You need to ask yourself how much power you want to try to achieve and what are the limitations of the rest of the engine hardware (i.e. stock valve springs, piston clearence,etc)

I am doing the same thing with an LS2 block and LS3 heads. I have a Lunati (#60514) cam but I need to change out the valve springs to accept up to a .600 lift because the cam is .584 lift and the stock springs are only rated to .570 lift. I've heard you can take the stock ones to about .590 but I don't want to run the risk of the springs binding up.

Take a look at the Lunati cam # 60511, it has a great profile and I don't think you would need to change anything else out.

[askkmb]

Thank you but since i dont want to spend to much money i want to use one of the cams from the 6.0 or 6.2 i have and i want to know what cam would work best or what would be the differences???

[Firebirdjones]

The cam for the older 6.0's are designed for the cathedral port heads. The 6.2's came with the larger square port heads and a different cam profile to exploit that (usually a rather large intake/exhaust split).

Basically in a nut shell, the heads you use will dictate the best camshaft for the combo.

[askkmb]

Okay so could you explain a little more why it makes a difference on the cam on cathedral port and square port heads???

[Firebirdjones]

The newer square port heads (LS3 or 6.2 etc) made a substantial improvement in flow on the intake side with those large ports, but the exhaust ports remained largely unchanged.

So you get somewhat lackluster I/E ratios. To make up for the exhaust side the camshafts are ground to favor the exhaust side a substantial amount. I've seen alot of the custom cams favor the exhaust side as much as 20 degrees for these square port heads.

I assume you are talking about running factory OEM camshafts in your combo? I don't have those specs in front of me but I would assume GM ground those 6.2 litre cams a bit differently than the old 6.0 engines with cathedral ports.

[askkmb]

Few words...good explanaition. Thank you everyone for the help. And yes im running just the OEM camshaft because i didnt want to spend to much money but hopefully later i can do an aftermarket cam.

[Firebirdjones]

I checked on camshafts since you are wanting to use one of the OEM's. I just looked at a couple of them.

The original 6.0's meant for trucks (with cathedral port heads) starting in 2001 use this....

196/207 @ .050 with .467/.479 lift

The LS3/L92 with square port heads used this...

204/211 @ 050 with .551/.525 lift.

As you can see GM didn't bother with much exhaust split on the square port motors, but the aftermarket sure does which tells me GM left alot of power on the table with these cams (obviously). Since you want OEM I'd go with the later camshaft, there should be a slight performance improvement with that even though it doesn't look like a great deal on paper.

In the later model square port engines GM started using variable cam timing, and things get complicated. I'm not sure exactly which example it is that you are working on but I assume it's one of the first two I mentioned.

[WICKEDLS1]

Im pretty sure the l92 is a DOD motor meaning it shuts off cylinders while under light throttle but i dont think that has anything to do with the cam selection. You should be able to install the L-92 heads with out a hitch but you CANNOT use your factory intake. You have to use an L92 or LS3 style and since your going this far go ahead and use the ls3 heads they are the best flowing on the market right now stock. Plus installing them on a 6.0 wil give you the opportunity to install a fairly decent size cam with out too much drivablility issue. However being an auto you will need a stall convertor i recommend Yank and depending on cam size any where from 3400-3800

[askkmb]

Yes mine is the 6.0 meant for trucks(LQ9 SS Silverado 2005) and with cathedral port heads. And the heads im putting on are from and 2007 gmc denali.
Thx.

[Firebirdjones]

Yes mine is the 6.0 meant for trucks(LQ9 SS Silverado 2005) and with cathedral port heads. And the heads im putting on are from and 2007 gmc denali.
Thx.

Cool, so you aren't dealing with displacement on demand and/or variable cam timing. Much easier and cheaper for modding.

[redbird555]

I just wanted to interject a couple things here. The early lq9's and lq4's used a rear cam sensor just like ls1 and ls6 motors. Therefore you cannot just bolt in an ls3/l92 cam as they use a front mounted cam sensor.

In order to make it work you would need to get the ls3 timing set, front cover, and cam sensor, as well as an extension harness to reach it. Also keep in mind that the cam from an l92 will not work because it is different on the front for VVT. You would need an ls3 cam to make it happen.
All in all this is way more expnsive than just getting a custom cam that would perform better for you while still being able to drive like stock with your stock trans. If your dead set on the ls3 cam then comp or any cam maker can custom grind you one.

Also the L92 does NOT have DOD it oinly has vvt which is pretty easily removed with a new cam, timing set and lifters. The l99 motor in the auto camaro is just a modified l92 with different cam, pistons and DOD.

[1nasty86]

do it right and find either a used cam in the classifieds section or stay with what you have now till you can... are you gonna mill the heads? i do know the ls3/l92 heads like a large split between intake and exhaust duration like a lsl/lxl 227/238 .614/.615 but thats just my .02...