I posted this on the Tech side, but thought alot of guys would like to peek at the potential performance of these new GM heads. Click here to view the thread.
For those not familiar with the new L92 engine, it is being installed in the Cadilliac Escalade. It's factory rated at 405hp and 417ft/lbs of torque. I'm sure GM will find other uses for this engine in the future.

I just finished flow testing a new stock L92 head. All I can says is…….WOW! What a nice part.
I’d like to publicly thank StreetnStrip for the opportunity to test this head.
The test head has casting number 5364. Here’s the tale of the tape……..

4.030” test bore
Lift ___.100 _.150_.200_.250_.300 _.350 _.400 _.450 _.500 _.550 _.600 _.650_.700_.750
#1 Int. 74.9 109.4 154.4 193.5 225.3 252.8 274.6 292.7 308.8 321.0 328.7 326.6 310.0 316.6
#1 Exh. 63.6 97.9 126.1 148.7 162.3 178.6 189.6 197.6 205.5 210.7 214.6 217.8 221.2 223.5
The intake was tested with a radius plate and the exhaust was tested with a 2 ˝” stub pipe.

4.155” test bore
Lift ___.100 _.150_.200_.250_.300 _.350 _.400 _.450 _.500 _.550 _.600 _.650_.700_.750
#1 Int. 73.8 108.7 153.2 192.6 225.2 253.6 277.0 296.7 313.0 326.0 335.8 326.9 327.3 317.1
#1 Exh.61.1 97.9 125.7 148.1 162.0 179.5 191.8 200.1 205.9 213.3 218.4 220.9 221.9 223.2
The intake was tested with a radius plate and the exhaust was tested with a 2 ˝” stub pipe.

Exhaust port tested without pipe (4.155” bore).
Lift ___.100 _.150_.200_.250_.300 _.350 _.400 _.450 _.500 _.550 _.600 _.650_.700_.750
#1 Exh.63.1 94.7 121.1 140.6 156.9 165.8 176.1 182.8 187.9 191.4 193.7 195.6 197.6 199.5

Valve dimensions:
Intake = 2.160” X 4.870” X .314”(8mm)
Exhaust = 1.590” X 4.920” X .314”(8mm)

Seat/throat diameters:
Intake = 1.870”
Exhaust = 1.355”

Volumes:
Intake runner = 260.6cc
Exhaust runner = 90.0cc
Chamber = 69.8cc

A few observations………. These heads have the best seat/port lineup for an as cast GM head that I’ve seen. Their casting precision is VERY good. The fit and finish of the valves are very nice as well. The intake port is large, especially the area above the short turn radius. The intake cross section starts at 3.1sq/in at the intake flange and grows to almost 3.7sq/in forward of the guide boss!
I’m a bit disappointed with the exhaust port flow. IMO it needs to be at least 25 peak cfm better. I’m sure the engineers at GM know what they’re objective was and they were satisfied with the final product but I think for hot rodding especially blown applications, the exhaust port needs to be improved. Looks like head porters will have something to do after all………
I understand that there is a company working on a 4bbl carb style intake, but I’ll leave the intake manifold subject for another thread.

Happy hot rodding.

Richard

 

WOW, now if the L92 truck intake could swap over, that could be a great setup for a stroker!

Thanks Richard!

 

Great data once again Richard! thanks mate

btw: I injected the data in your first post for easy viewing

 

Nice... Except for the exhaust as you mentioned. I can hardly believe those are stock heads lol. The intake side flows very close to my stgIIIs.

Thanks for the heads up Richard -- great to see someone taking the time to do stuff like this and making the info public.

 

WOW

320+@.550 as cast from GM with a 2V head thats amazing, I think a larger exhaust valve will help with the exhaust flow specs 1.59 seems a bit small for those heads.

 

Must... buy... L92's for LS2 stroker project...


Heh, who needs 3v/4v/5v heads when GM can break the bank with a 2v pushrod engine

 

i know who's heads you tested

 

Very interesting numbers for a truck head!!! Have you had a chance to go over a set of LS7 heads yet? Reportedly they've gone over 340 CFM on a few benches already and I'd like to see how they compare on your bench. Nice work!!!

 

I tested the LS7 heads a while back. You can click on the link to see the results. LS7 flow results
They have a great intake but a poor flowing exhaust.

Richard

 

rich, this is off topic but your the older 6.0 heads work fine on our 5.3's? Im sure you would need to mill them to get CR up some though.

Im sure the new heads will be gold prices though but the old 6.0 heads should go for cheaper now maybe. I was just wodnering if they would be worth it as a direct swap for stock 5.3's