Big-DEN

The L92 did not feature hogged out ports, it featured a head with a slightly smaller runner than the LS7 head. The intake runner was raised even moreso than the LS7
and featured very good flow even at lower lifts.

The head alone as it stood from the factory was good for 700HP or so N/A. With boost as far as you'd like.

The real question is how do the L92 head/intake manifold flow together as a unit.

The LS7 head alone does 360ish at max lift, where the LS7 head/intake does 320ish at max lift. Still better than any of the ported plastic intakes and ported LS6 heads.

"Gregfell" on this BBS ported the LS7 intake manifold, made some small modifications
and got the LS7 head/intake to flow 360ish at max lift with very little flow dropoff.

Cop Car

iTrader: (14)

i dont care, when you can pick up a set of L92s for 800 bucks, and probably get ported ones for around $1500 it makes heads like AFRs pretty much obsolete. when you have the possiblity of making 500rwhp N/A with stock heads from GM, the aftermarket better get their prices down fast otherwise nobody will care that you can buy AFRs for $2000 that flow 351 CFM when you can buy ported L92s that flow 350 CFM for $1500

*Tard disclamer*: those are just random numbers made up to prove a point

SStrokerAce

iTrader: (2)

This ain't just about flow/CFM fellas.... you are all trained to think that way but it's not what makes a cylinder head make power or get down the track faster. It's EVERYTHING.

Bret

BigBronco

iTrader: (2)

Like stated earlier, Jesel has not made a Rocker stand yet... we are still waiting as we are doing a set for a solid roller setup.

BigBronco

iTrader: (2)

Yep, the whole picture, Runner size, CFM, the velocity around the entire port and keeping a good average, etc. CFM only gets you a portion of the picture, and the power

Nine Ball

iTrader: (38)

Keep in mind that aftermarket castings have other benefits than just CFM ratings. They are also beefier in areas that are prone to failure, have a thicker deck to reduce warping or lifting of heads, bigger spring pocket areas, taller valvecover borders, etc... So, they still have some nice advantages. CFM isn't everything.

SStrokerAce

iTrader: (2)

That's what I would say too if the aftermarket head companies were paying the bills ;-)

Joking aside those are good points..... what BigBronco touched on is actually more important in terms of power. You can do other things in the design to help compensate for issues that a OEM casting gives you, and I've heard that the best blown setup one place has done to date was with the L92's. Only guys really pushing it like W2W with cylinder pressure will have the NEED for the super thick deck and rigid castings to keep the heads on the block.

Bret

SPANKY LS1

iTrader: (24)

Well, I was referring to a NA setup, so the casting strength issue isn't a factor to me specifically. I know that there may be better options, maybe my post should have asked the question, can any aftermarket head/intake combo match, on a HP/$$ basis, the potential of the L92/L76 combo in an NA application?

I'm eagerly awaiting some results on 4" bore motors, such as *cough cough* C6s. I am sure that ETP/TF/AFR combos are probably capable of matching and even outperforming this combo, but I'd like to see what a TEA/MTI/other porter here can do with a head that flows 320 cfm as cast. Once ported by a reputable porter, these ported L92 head/ L76 intake combos could potentially be signifigantly less expensive than the current aftermarket options.

That being said, I'm not gonna be a guinea pig, I'll wait for some real world numbers before I make a decision either way. As of right now, the ETP heads and the TrickFlow stuff is putting down some stout numbers, and are as of right now, the more proven commodity.

Shawn

427

iTrader: (3)

The L92 and LS7 stuff is great, it will be on many performance builds. The problem will come with those that need a more rigid platform. I look at material type and certain features that we require on certain builds. Both type of heads will have a place in our little corner of the internal combustion world!!

Kurt

Wnts2Go10O

iTrader: (12)

dont the LSx heads have an issue with too much velocity? (thats what i read from one of the more knowledgable people here) thats the reason why i would think these heads would out do the LS heads. comparing the 2 i see it as engineering the heads to slow down the air just enough to make that turn easier. granted, it flows amazing, has a massive cross section, humongous intake valves, and godly oem machining, but i think the magic lies in the short side more than anything else with these heads.
god only knows what will happen when more head manufacturers make copies of the ls7 and l92 heads or even how gm will top themselves

Dragaholic

iTrader: (180)

Ok...seems like I'm in the same boat as the original poster. I'm VERY undecisive and just when I think I have a build put together, I read something new.

I can't decide between these setups:

LS7 block (read that block will be going down in price)
LS7 heads
LS7 intake

L92 block
Aftermarket LSX heads
FAST 90mm intake

L92 block
L92 heads
L76 intake

I'm not really on a budget, BUT, I don't have an unlimited amount of money to spend on this motor. I'm torn between a LS7 block and L92 block. Need to decide on that first, then I can decide on a head and intake combo. Either way I go, its going to have a minimum of a 4" bore as the L92 comes with a 4.065" bore and the LS7 comes with a 4.125" bore. What do you guys think would be a good combo that won't cost an arm and a leg, but isn't necessarily a budget build?

gollum

iTrader: (1)

Buy the LS7 427 Crate motor but change reluctor wheel to LS1 version so combo will work in your Camaro. You will also need cable version throttle body and bigger cam of course.

MeentSS02

iTrader: (11)

I know I'm pretty much retarded in this world, but I don't think the heads are the issue at all...it's the intakes. The LS7 intake sounds killer, but features a bottom-in opening throttle body that is very hard to duplicate functionality-wise on a cable driven TB. And now people are finally getting their hands on intakes that can fit the L92 heads, but no one knows how they will perform compared to a cathedral port intake. We have great flowing heads without the intake manifolds to match. And going sheet metal isn't the answer for a street car.

I guess I'll just sit idly by while the aftermarket gets this worked out. Maybe by the time I'm ready for a new engine, it won't be as hard to piece something together as it seems right now.

Bandit28

iTrader: (28)

Eventually the L92 and L76 may take over but not until you get a good port job and a better flowing intake.

SStrokerAce

iTrader: (2)

More like the velocity profile is the problem with LS heads..... and yes the tall short side radius on the L92's is one of the many reasons they rock.

Bret

Cop Car

iTrader: (14)

in most cases its not, but a single plane carbed intake is the answer for everything

Wnts2Go10O

iTrader: (12)

id personally like to see a tunnel ram type intake

Cop Car

iTrader: (14)

like on the old 69 Z28s? the cross ram.. now that would be freaking sweet

ASRoff

Lets just say that I know of some L76 Intake testing that dident come out so hot.

LSPerformance

iTrader: (23)

What did the manifold flow?