i am sorry, but did you look at the link i posted? heads and cam and it made just a few short as what you did with an entire larger CI engine. i think there is something wrong with your setup.

i am not arguing that the tfs heads can do alot of things, but you are also underestimating the l92 heads and what a proper cam can do.

 

I saw,and it was powerful too.. On my ls1 I had no ud pulley,a non touched intake,a 12 bolt w/4.11's and 13.50 yolks in the trans and rear on a mustang dyno that dynoed way lower when I had the car on two jets. I could of went to a jet I was on before and claimed a 25hp gain from that. I ran 11.1 n/a on that set up in a 3,700lbs car with me in it. I don't think anything was wrong with the set up. lol. I was told a l92 head flows in the neighborhood of a 235 head. So,it should make more power then a 205cc head on a bigger ci motor like a ls2 over a ls1.
My buds 383ci made near 500hp and 478tq with a non ported intake,no ud pulley,9 inch,**** headers,no cats and a STOCK camaro ss catback on the same dyno I'm on. It's the heads. lol
Remember,I'm not bashing the l92,I have them on my car. I just really think from past build up's and my boys car they are a better head for performance,just not better in price. Dollar for dollar the l92 head is the way to go if you're trying to keep cost down.
Before anyone says then why are they not on my car if I love the trick flow so much. Because I'm sick of spending on this car,so it's the cost for me.
Be cool guys.

 

John,

I bought my L92s from you guys a few months ago. Still gathering parts for my ls2/l92 swap. What would you recomend for a cam with a stock bottom ls2 with your l92 heads. Im also running a 3:90 gear in the back. Car is a weekend driver/summer toy.

 

take a look in that thread. we can make one just like that and it drives almost exactly like stock. barely a "cam" burble. its very impressive

22x/23x cam with some .61x/.61x lift and a good lsa and you are on your way

 

I love my L92s...get a cam matched for the heads and you're good to go.

 

I'm not a big fan of L92's on a 4.030 bore. I like more clearance. The intake valve is so big is remains shrouded by the cylinder bore at lift. I would opt for a nice set of cathedral ports for a 408.

 

what type of lobes? also tying into your other thread about ls7 lifters, would that be a sufficent lifter for a cam in that area?

 

The car we used a cam like that in will see almost 98% street duty or more really. It will not be raced often or see much above 6500. So we used LS7 lifters on that one. They would be sufficient for that cam in that intended purpose. I am not sure on the style of the lobe, maybe it says in the thread.

 

Xtreme Energy LSL 13016
Xtreme Energy LSL 13018

 

Ok. So. Like i have said numerous times before......the intended purpose plays a huge roll in what the final verdict is.

 

Isn't that the truth!
I have watched this thread for a few days and I agree with John. The L92 is a good production head that lends itself well to mild performance applications.

Once you get into serious RPM, Cylinder Pressure and Valve Spring Pressure you need to step up to an aftermarket head. These things have been addressed by GM Perfomance Parts as well with their new LSX LS7 and LS3 heads.

I have no problem with the installation of a L92 head on a 4" bore. I was very surprised at how well the LS2 responded with the heads. Hell all my G8 buddies are running this deal from the factory

BTW GMPP now is shipping loaded LS7 and LS3 intake manifolds again.

I have a set of GMPP CNC Ported heads on my LSA crate engine. That head (the same casting as the LS3/L92) is supporting close to 700 horsepower. It should go for another 100



Robin

 

what upgrades were done to the ls3 casting?

 

If your talking about the GMPP LSX LS3 head then there are several upgrades.

More material in the deck.
More material in the ports
Larger spring pads
Provisions for use on a 6 Bolt LSX block.

Robin

 

PMed you Robin.

 

Hi Robin,

Do you happen to have any information on the new LSA / LS9 heads in the 2010 GMPP catalog? The Powertrain Contact Center did not have much to say about them besides what is printed in the catalog.
I know these are production heads, but I am thinking that since they are made of better material and have "thicker" decks, that they might be worthwhile upgrade from a LS3 / L92 head for a boosted application.
I am not looking for 1500+hp, but I would like to have some safety factor for another 150hp to give me a shot at high 8's at 3,200lbs.
I am currently at about 900hp flywheel on stock L92's but I am hearing that I am likely at the "safe" power limits already.
I think running E85 will help keep peak cyl pressure down, but it will only be a matter of time until I start having gasket issues.

Being a new hyd roller 4-bolt engine on a budget, I'm not ready to jump into the 6-bolt setup yet.

Thanks for your time!

Jim

 

They do some with some NICE lightweight valves. I am suprised no one else wants to use them in a "total lightweight" build. Titanium 2.165 intake and sodium filled 1.59 exhaust in L92 fashion.

 

Yep, John is correct on the LS9. The LSA has the same valves as the LS3.

The LS9 has larger 12MM head bolt holes compared to the 11MM standard size in the LSA heads.

Both heads use a vane in the intake port to add swirl at low RPM and air flow. I don't care for that vane and that is the reason why I swapped the heads.

Since that time I have talked with several shops who have done a lot of testing with the LSA and LS9 heads. From what they say when boost is involved there is no loss in performance with the vane. On a flow bench they fall off but of course a flow bench doesn't duplicate boost.

Also as mentioned they use a different process that makes them stronger than the standard LS3/L92 casting.

I was told that the vane really aids in Low RPM idle.

I have also heard the decks were thincker as well. Hopefully I can confirm this when it gets warm enough to venture out of the house

Robin

 

To be clear, from what I am told the LS9 has the TI valves and the LSA has the Hollow stem LS3 vlaves.

Still both lighter than the L92 valves

Robin

 

The misconception with L92 heads "not making power" comes from not looking at the specs all around. For peak HP major race applications, they may not always be the best, but in a h/c street car they are incredible. They completely change power delivery from the peaky cathedral port setups with big cams to major low end monsters with smaller much more friendly cams and still near the same pk numbers. They make killer power from much small cams, and they make TQ so early. With CNC heads and the same cam John mentions above in the 22x/23x range we have made 478rwhp and upper 45x rwtq on the stock LS2 bottom end and it idles and drives absolutely like stock. Note that those are unmilled heads and stock gaskets, so you are dropping the compression quite a bit from stock and still getting that HP and TQ. That cam leaves room for a thinner gasket and/or milling for compression and could make even more power with even better manners.

Like with most arguments on here, people simply argue peak HP numbers when that is in no way the whole story. Average hp/tq means alot, and where it makes the power.

 

Strange. I ordered some for the LS9 heads...and that is what they came up with. GM lookup and the 09 GMPP mag says that the LSA uses its own intake valve, but it is solid stem. Not that i am questioning you, but I would like to know for myself. May have to order some of them in and post up what i find!!