anyone install the L92/76 intake yet with the stock cam and exhaust manifolds?

These heads are selling for about $800

would be an interesting swap onto a bone stock C6


edit:Jan 03, stock cam is just for comparison sake, most upgrades will add the cam and springs(about $800 in parts)

 

To date I have only seen them used on a 403 with disappointing results. 480rwhp.

 

Steve, don't know yet but with 30 more CFM over most aftermarket and no "curtain" you have to expect 25-30 RWHP...only that stock cam will limit.

 

Not only the stock cam but also the larger combustion chambers of the L92 heads could be an issue, might have to mill them down a little bit to keep that compression ratio up.

 

480 rwhp is a bad thing for 1200 bone including fully assembles heads, intake, injector, rails and t body.....

 

great point....

 

Well for a 403 with an aftermarket cam it is yeah (if that was the set up he was referring to making only 480rwhp)...and a set up like that costs more than $1200.00 as well.

 

the combustion chambers on the L92 and LS7 are both 70cc, 5.5cc larger than the stock LS2 heads

I'm looking for info on installing them on a stock LS2, what the gains would be

 

I dont think anyone has done that, yet....

 

IMHO, minimal gains, if any at all.

Compression would be down, port velocity would be down, oversized valves would be shrouded. The excellent flow capacity would never be achieved with the stock cam.

Classic case of mismatched components.

 

I'm interested in having the L92 heads and L76 manifold installed on my stock LS2. This was an interesting related post. I found info on GM Performance Parts website. See my second response post #20 of this thread.

http://forums.corvetteforum.com/show....php?t=1579423

 

I went to the GM website, very slick presentation. According to the buildup w/ the new heads/intake combo, power is decreased up to 4200 RPMs or so, after which there is a power increase. This is also using a "mystery" (no specs provided) hydraulic roller camshaft that is not in the parts book. Result is an increase of 40 HP on the engine stand, or about 34 RWHP. Many straight cam swaps will provide similar power gains.

Also reading elsewhere in the thread, it appears that higher tension valvesprings must be used, plus special offset rockers for the intake valves. The thread also implies that the heads must be milled to regain the lost compression caused by the larger volume combustion chambers.

Also, I have read elsewhere that the D-shaped exhaust ports require special exhaust manifolds --- MAY require custom headers. Exhaust components are not included in the GM virtual buildup.

All in all, this does not seem to be a simple bolt-on mod for a stock LS2 engine. For the money, I would think that a straight cam swap would yield better results. perhaps even better power under the curve.

To be fair, it's possible that GM is actually offering a special version of the heads that has been optimized for the LS2, with the correct valvesprings, rockers, & compression ratio. Without actual specs, though, it's difficult to tell.

 

http://ls1tech.com/forums/showthread.php?t=617034

 

The Livernois test results were using a 232/236 .600" cam, not a stocker. Very encouraging that the lower-RPM TQ numbers were so high --- port velocity must be pretty good.

 

It is when Lingenfelter got 476 to the wheels with a 403 with bone stock LS6 heads.

 

Are you kidding me?
I LOVE your posts, Spin.

How much does LPE charge for a 403ci short block installed?

The L92 parts are only $1,200 and you can SELL your LS2 parts.
So, the L92 stuff ends up only costing you a couple hundred dollars and you can install the stuff in your driveway without a lift.

Thanks again for the GREAT info Spin!

 

Yes, Spin --- thanks for the great info.

Lets see, 4 HP for $1200 --- sounds like a real bargain!

Oh, right ---- you can sell your existing heads & intake. So, let's say it's an even swap. 4 HP, just by swapping out your heads & intake!

 

What are you basing your numbers on?
Can you explain your post?

The L92 TRUCK heads and intake picked up 32 hp and 44 trq over the LS2 head and intake on the same motor with the same cam.

Correct me if I'm wrong,
but I think that is a decent improvement for a minimal investment.

 

Hopefully I will be able to shed a little light on this in early February...although the car is a turbo car. I plan on switching from the 243s to a ported L-92/L-76 combo with no cam change.

 

My post was based on Spin's --- same as yours was. One 403 had the L92 heads & intake, made 480 HP. Another 403 had stock LS6 heads (didn't specify the intake), made 476 HP. 480 - 476 = 4 HP. What part is it that you don't understand?

If the L92 heads, right out of the box and without any modifications, really picked up 32 HP and 44 TQ over the LS2 heads & intake, using the stock cam, then I am suitably impressed, and would agree that it's a real value. Not only that, but it addresses the topic of this thread, which is whether it is worthwhile to use this package on an otherwise stock engine.

The test results cited in this thread are using an aggressive aftermarket Livernois cam. The heads also had stiffer springs installed. According to the article, they picked up 44 HP and 29 TQ - different numbers than above, but still impressive.

So, for those considering a heads, cam, intake, and headers swap, using a fairly big cam, sounds like this might be a killer combo. But so far as bolting this onto a stock engine using a stock cam, I have my doubts.