mistafosta

iTrader: (9)

Anyone have any experience with these heads under boost? My 243s are a huge bottleneck in my setup and I'd like to try something else that I can AFFORD (Im poor as hell)

Im running a D1 at 9psi currently with an untouched 243 head and matched springs/retainers. Would want to goto a pretty much stock l92 head/intake setup.

What kind of power have people been making on these heads with boost? Do I have to change other stuff to fit? (TB? Rockers? Different valve springs?) I want to make sure I don't end up buying some heads that cost me an extra grand just to make fit correctly.

Working with an ls2 block so the bore should be matched decently

allthrotle

iTrader: (2)

You have change the intake manifold, you have to run the L76. the rocker arms are different because theyre offset on the intake. You have to change your throttle body to an ls2 tb if you dont already have one because the new intake is a 4 bolt pattern and not a 3. The valve springs you should be able to swap over from your old heads.

mistafosta

iTrader: (9)

Thank you, I appreciate the info.

As for doing a DEARCH, I did, and I would prefer more current info since these are becoming more common and so people should have much more information on them then cryptic "they will crack over 700hp" answers without any info backing it. So next time you wanna be nice and helpful like that, help yourself to a can of STFU and don't click the reply button.

Back to topic. Has anyone confirmed the cryptic cracking issues? What about all the high HP guys that now have been running them for awhile? Any issues? Happy with the performance? Ect?

PICNIC_GEORGE

iTrader: (3)

Is this how you keep your post count up? Maybe he did a dearch and yielded no results..... I tried the dearch button and got nothing.

Fosta you looking for something ported or off the shelf?

mistafosta

iTrader: (9)

Id love ported, but Im poor as hell so thats a big controlling factor. The flow numbers are 330 @ .600 untouched on the intake side which seems like a huge jump from my 243s.

Ive been seeing stock ones for less than $1000, thus why these perked my interest. So far the only failures ive seen are on 1000hp cars and I dont plan to make that at least for another year or two.

PICNIC_GEORGE

iTrader: (3)

Stock ones with a good port on the exhaust side will pick up some good power on your car I'm sure... You should be where you want to be with a set of those. I'm sure someone with a lot more exp. than myself with l92s can chime in.

veee8

iTrader: (40)

I wouldn't recommend them for much more then boosted 600hp. Any time I ran a moderate amount of boost, I had lifting issues.
Looking back, I wished I would have waited a little longer, and spent a little more money on a set of aftermarkets back then.
It would have saved a bit of grief.
There just is not enough meat in them for a good clamping load or room for 1/2" studs.
See here.....
https://ls1tech.com/forums/11579636-post13.html

allthrotle

iTrader: (2)

No prob, any friend of picdic is a friend of mine.

L92 heads are great heads, with some port work to the exhaust side and you've got a good flowing head for cheap. Ive never heard of this cracking problem that you speak of though but, I dont have any personal experience with them.

mistafosta

iTrader: (9)

So they are weaker than my 243s? Yah, 600 is way below the level of power I would be making on them... Im just trying to find something I can afford, cause all the aftermarket ones are way over my price range...

veee8

iTrader: (40)

I don't know if they are weaker, the GM castings would all be comparable in that department.
I was in a similar situation, and the low initial price was attractive on the L92's, but once the specific intake, offset intake rockers and rockers stands are factored in, they start to loose their value. They have huge heavy intake valves, so you need to make sure you have a good set of valve springs to keep up with them and boost.
Depending on hp goals, saving a few bucks on them, don't outweigh the advantage of a aftermarket casting in a boosted application, in my opinion.
Others will argue that though.

180ls1

iTrader: (4)

they are weaker then your 243's because thay have less deck height, if i were you i would just go with a ported version of your head so you can take advantage of your 4'' bore and have larger then stock valves.

BigRich954RR

iTrader: (1)

LOL What are you thinking here? 600HP is way below your power level ? Whats you power level ? What are you going to use to push the air in and how much psi ?


Yes there weaker and few poeple have cracked them ?

When you getting into boost you dont need great flowing head reason people have done well with 243 heads

108dragon

iTrader: (5)

Don't let the fact that they are stock castings scare you. Dispite they were never GM tested for the power levels people push them to, they have passed all GM durability testing. For the money, find a set of LS3 821 semi perm cast heads. They'll flow exceptionally well stock, have the hollow/sodium filled performance valves, and the LS6 performance springs to begin with. They will offer a 100% improvement over your stock 243s as is. They have been used in applications in access of 1000hp. Preventing detonation and proper sealing are keys to successful use.
The fulcrum issue here is unfortunately your budget. The LS3/L92 heads will work admirably for you. But you will need to switch out your manifold, throttle body, and intake rockers, and add some other supporting mods. Keep your lift under .570 or so and the LS6 springs shouldn't be an issue. Definately go with ARP studs with your combo -at the least. Just cheap insurance.
Something which needs to be addressed and is often not with these heads is the intake to exhaust flow ratio issue with these heads. You will need to hit up PatG, PredatorZ, or someone of that level of expertise in cam design to spec out a cam for you to optimise your combo with these heads. Definately worth the few extra dollars.
Just my learned 2 cents.

mistafosta

iTrader: (9)

Yes, 600 is was below the power level I would be making with those heads. I would like something that is safe to 800rwhp or so.

Im sure people have done well with the 243s, but there is a point where stock243 flow #s just dont cut it even with boost and I am pretty sure I have reached that...

veee8

iTrader: (40)

Save your money and get a set of aftermarkets heads at that power level.
Heed my warning.......

pwrtrip75

iTrader: (8)

I have a set of bare L92's I was going to put together for my 421, but after seeing this and been reading about it for awhile im not going to bother. I'll find an aftermarket set as well.

veee8

iTrader: (40)

You will be so much further ahead with a solid set of heads. Nothing worse then having a turbo car that you can't crank the boost up without worrying, because of being held back by GM heads.

BigRich954RR

iTrader: (1)

Im a huge fan of aftermarket head first off. so if you have the money buy them.

But why do you think you reach the limit of stock head ?

Few people were in the plus 800 range with all stock 243. There one guy with close to 1000 i think round some where

mistafosta

iTrader: (9)

No porting, and no extreme cams? This is a 100% street car that is daily driven, and makes good power so far. (10.6 @ 136 with bad traction) Turning up the boost from 9-11 lbs netted no power increase (With a tune also of course) Looking at my setup, the only obvious bottleneck is the lack of flow in my heads.

I will hold off on changing heads to these due to the reccomendations against them. Guess Im just gonna have to be happy with the car as is, and move on to my fast car again..

Shawn @ VA Speed

iTrader: (3)

if you went from 9 to 11 psi with no power increase,you have other problems,not the cylinder head,i would be looking more at the tune or an exhaust backpressure issue-not the cylinder head.

As Veee8 has said the l92 casting is very weak,while there has been a couple cars over 1000whp with those heads-none that i know of has lasted very long before having head gasket issues.