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LQ4/9 + L92 heads & manifold = ???

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Old Sep 21, 2006 | 08:14 AM
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Default LQ4/9 + L92 heads & manifold = ???

Hey guys. I would like to know if anyone here has managed to install the L92 heads and intake on their LQ4/LQ9. It sounds like it should work, but has anyone actually done it?

I'm surprised there isn't more talk about it here.......
Everything I've read on the L92 heads/intake is positive - $350 heads direct from GM, all complete with great flow numbers straight out of the box, manifold complete with 90mm TB & #44 injectors - sounds like a cheap performance upgrade (is there really such a thing?) if it can be done.......

Anyway, if anyone has done it, what else was needed? Were you able to re-use your exhaust manifolds? What about TB wiring, did that present any problems? Fuel rails - are they a return or returnless system? Anything else I need to know?

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Old Sep 21, 2006 | 11:39 AM
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Look over on tech in the internal section there is an L92 sticky with all the present info on it.
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Old Sep 21, 2006 | 01:36 PM
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what are the l92's coming off of?
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Old Sep 21, 2006 | 01:45 PM
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Originally Posted by onebadrubi
what are the l92's coming off of?
The 6.2 in the new Escalade's and Denali's.
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Old Sep 21, 2006 | 01:53 PM
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You'll need new rocker arms to go with the heads.
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Old Sep 21, 2006 | 04:33 PM
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Originally Posted by 1slow01Z71
Look over on tech in the internal section there is an L92 sticky with all the present info on it.
I've read all the threads on tech and couldn't find the info I asked above. All I saw was pages and pages of "will they fit my xxx?" and "when will they be available?" etc, etc.

Could you show me what post you are referring to please?

Originally Posted by vanillagorilla
You'll need new rocker arms to go with the heads.
Yeah, OK, I read that too, but they aren't that expensive, are they? Seems to me to be a small price to pay if that is all that is required to get them working......

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Old Sep 21, 2006 | 06:18 PM
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As of yet I dont think anyone has gotten the "package" from GM yet, I dont think the manifold is available ATM.
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Old Sep 21, 2006 | 08:16 PM
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The only thing different in fitment basically is the intake ports in requiring the L76 intake or carb intake(which isn't out yet). The L76 intake is an Aussi build and are going for $700+ on ebay. I have a set of L92's and am waiting on the carb intake to be released. I haven't built mine yet. An LS1/LS6 intake will seal on the intake ports but they don't match up well and should only be a temporary fix, which is what I will do until the carb intake is released(since I have already done the mods for it). The later truck intake gasket will not seal due to it tappering at the top(not sure what year they changed the gaskets or if they ever did). The older seals (LS1 I know for sure)are rectangular and don't follow the cathedral port.

The L92 info sticky on LS1 tech has a lot of good info in it if you can sift through the crap. The people that get on there and ask the general "will these heads work with my xxxx" questions are lazy and ought to be banned!
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Old Sep 21, 2006 | 09:57 PM
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We're in the beginning stages of working up a CNC port program for these heads and I can tell you that even straight out of the box they flow a bunch on the intake side. The exhaust leaves a bit to be desired.
These new heads have pretty large (volume) intake runners (260cc ) and may cause a loss of low end torque in 6.0l truck engines that use longer duration cams such as 224+º. These heads are ideal for engines in smaller lighter car type applications which is why they're so popular with the car crowd already. That being said, they can make for a nice N/A stroker 402 setup or a std. 6.0l with a power adder.
I'm not exactly sure why GM chose to install these heads on a truck first, but they did. Evidently they've figured out how to time the valve events to maintain low end grunt and driveability. The high intake flow handles the mid range and top end torque.
Lastly, always remember to try and choose a smaller duration cam when installing these heads and intake in a truck application. My best guess would be to down size the cam by 8-10º duration.
We should have a bit more info about these head swaps on 6.0l engines in the next couple of months.


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Old Sep 21, 2006 | 10:08 PM
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im planning on using these heads for my 370 / blown set up , does anyone know if the truck intake for the 6.2 is available? does anyone know if the heads can be bought assembled from gm? part #?

a link to the sticky would be good too.
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