Well on a side not, are the 243 (LS2 heads) stronger than the L92 heads, in a forced induction application? Given all variables are the same... Sorry for the highjack but I'm in the same boat as many of you when it comes to head selection for a daily driver. I’m trying to get the most horsepower out of a set heads for the least amount of money. I know I'm cheap, but hell I'm not about to go in debt or dip into my children’s college fund just to go a little faster or to when a pissing contest.

 

in the same boat thats why i posted this thread just had a new born 5 months ago.....lol

 

Can anyone else chime in and give us an answer to the previous question? Refer to post #21...

 

if you want a daily driver that can turn 750 on the flywheel and nothing more, then the l92 heads will be the best for the money
If you plan on making a daily driver that puts more then 750 go spend some more money a good set of 243 PORTED will make a ton of power! but u will pay for them

 

Well I guess I didn't really make myself clear, is it worth it to convert my ls2 over to l92? Better question, what would a stock bottom end LS2 (APS twin turbo) make with the stock 243 heads and the L92 heads? In other words can I make just as much power with the 243s as I could with the L92s in a twin turbo configuration, with stock bore, stroke, and cam?

 

I wouldn't tear apart a good running engine to go to L92 heads.
The stock lower end will limit the HP potential far before the heads become a restriction.
The L92's will make a little more power than the LS2's at the same boost level, but that's what boost controllers are for!
I would say you should just upgrade the springs and leave the LS2 alone until you decide to go with all forged internals.

 

Well i bought another project car recently and was looking at doing another boosted motor in the 700rwhp+ range (gunna take some time puttin this together).

First I was looking at the Stage 2.5 317s from texas speed or the L92's....

From various peoples experience, what would you go with??
I do not have a intake/fuelrail/TB yet so either route would be the same difference, except the ported L92's are a few hun cheaper

 

I had really wanted L92's myself for the out of box flow vs money. However I put my thinking cap on and wound up with a set of as cast All Pro's. Glad I made this decision. Hopefully I can get it running soon, lol.

 

Anyone else want to chime in and give there opinion on 243 vs L92. Will both of them push water at the same power lever? Or will one have more flex than the other?

 

I dont think there can be much of a difference.

Only thing better than any stock head would be an aftermarket piece.

I just got me a set of L92's with work done to the exhaust side. Also scored up the LS3 intake and rails!

But I plan on the 700-750 rwhp mark. According to all the shops that i've talked to, they will work good.

 

My questions is this: Hasen't everyone who has taken these heads past 900rwhp and had a problem with the heads lifting or breaking, had detonation or some other issues that could have contributed to the head failures they experienced?
Is it pressure breaking the parts? How much can you spray these heads?
We all agree the deck is thin. How did we arrive at 750 rwhp instead of 850? Is it to keep the engine hp under 1000? Thanks

 

Can anything be done to make these fragile heads last any longer @ 900rwhp? O-ringing, E85 rocketfuel instead of E85 at the pump which can be inconsistent at times. Thanks

 

I was having problems lifting even without detonation, pretty much right from the get go.

 

That sucks big time. I built everything to handle 1000rwhp and these heads seem to be the weak link in the package.
I guess I'll have to figure out my next move.

 

I hear ya man, I choose the L92's when they first came out, and didn't really put much thought to deck thickness. By the time I bought stainless valves and had them ported and assembled, I was very close to just going with a aftermarket head. Even some basic Trick Flows or AFR's would be a wise decision in my opinion. You can band aid a factory casting with tricks, and there will always be people out there to argue that they work great, but the aftermarket heads are way better right from the get go, combine them with a Virgina Speed double o-ring setup, and you will have zero issues with lifting heads again.
I ended up with the heads that I always wanted, but never got because I could not afford them at the time. ETP LS7's and Va Speed double o-ring setup. Should have waited and done it right the first time.

 

You said a mouthfull. I will probably go to an All Pro head. I've got enough in mine to have a good set as well. I feel stupid because deep down I knew this wasn't the best way to go. Fun times.

 

I just made 847/ wheels with the L92s on 16# boost yesterday. Plan is to run it on a few less lbs most of the time, hopefully she lasts a while

 

i refresh it to let people know about the issue with L92 heads

 

its been over a year... and wonder how everyone is doing with them now?

 

i made 988rwhp thru a th400 and 9inch. i later sold them to get some GMPP lsxLS3s. i pushed water with an oring setup. 18psi