Generation IV Internal Engine - wheres all the lq9s?

collectively ive done about 3 hours of reading and searchin around for someone who has done a build close to what i want to do and cant find much.

last week i almost bought an ls6 shortblock to build but then i started kickin around the idea of a lq9..... then i started searchin and cant really find anything to impressive yet

my goal is to make atleast 500rwhp. id be happy at 500 but theres nothing wrong with a little more

but cant decide between a ls6 or lq9 only from what ive seen so far,

id figure a lq9 with a big ol' cam either shelf cam or spec'd out from pat g or so, along with a ported FAST intake AFR 215 or 230 heads with a small combustion champers pulleys throttle body to match the FAST long tubed and full exhuast....of course ARP all around and big injectors maybe some different pistons



are you just not going to see 500rwhp with that or not? all i can find is people using stock heads and such

would a lq9 have to be stroked or bored or both to see these numbers?

or is it gonna be the same as doing all the same mods to an ls6 with give or take 20-30 hp ?

Instead of dropping the money on afr heads, put an ls3 top end on it. I have a 370 with an ls3 top end, (stock heads and intake) and I'm shooting for 500.

People are making 500 at the wheels doing ls3 top end swaps on ls2's with a good cam. No reason it can't be done with a higher compression iron block.

Instead of dropping the money on afr heads, put an ls3 top end on it. I have a 370 with an ls3 top end, (stock heads and intake) and I'm shooting for 500.

I'm doing the same thing except on a stock LQ9 bottom end (rebuilt with clevite bearings, total seal rings, arp bolts). I'd like to see mid-high 10s N/A (around 460-470 to the wheels).

People are making 500 at the wheels doing ls3 top end swaps on ls2's with a good cam. No reason it can't be done with a higher compression iron block.

Do you have any links to some of these? I'd like to see their setup compared to what I'm doing.

I'll dig one up when I get home. There is a thread in the gen 4 internal engine section of a vette with an ls3 top end putting 500 ish to the wheels.

I'm running (in work) a 96mm TB, 1 7/8 Hooker LTs, EPS cam, 4k stall (TH400), M9 (3.89s, may go steeper but I have plans to hit it with a 100 shot), target weight is 3300-3400 with me in it and the 10pt moly cage. I'm not too concerned with a dyno #, I just want to see 10s off the bottle. However, if my setup is along the lines (at least close) with a 500 rwhp car, it should have 10s in it with the suspension dialed in. Sorry if I hijacked your thread at all OP.

nahh didnt hijack it..............terrorist...... jk haha

i just want some info from someone see some builds..some numbers.. somethin

i looked around youtube, guy had a pretty stout lq9 on a dyno...and he only made like 435 to the wheels... i have to hit at very least 500 to wheels.

"bww388" what sort of info do you have about ls3 top end? benifits over after marketed top end?

any one else feel free to put in info

btw i have an m6 and will be running 411's through a 9inch eventually

300 + cfm on the intake side bone stock...I picked up my brand new ls3 heads for 700 bucks. These heads will flow more than enough for a 6.0 right out of the box. Combine them with a custom cam, up the compression a little and put a fast intake on it, and I don't see why you wouldn't hit 500. Only problem is your either going to have to fly cut the pistons or change to a forged piston with valve reliefs. The huge intake valve does not leave a lot of room for a larger cam, although, the ls3 heads flow so good, a huge cam is not necessary. Which means less aggressive lobes and longer valve spring life, and better driveability.

I too have an m6 with a 9 inch and 4.11's.

I'm going with a 90 mm tb on a stock ls3 intake with an ls7 maf and a 98 mm lid. 1 3/4 to 1 7/8 headers back to dumped duals.

hmm i hear ya, ill have to do some reading on the ls3 heads for flow #'s.

the engine will be ripped down anyways im fine with fly cutting the pistons, no big thang there. whats the numbers on your ls3 heads for reference (i.e. ls1 "243" heads) ?

http://m.ls1tech.com/forums/showthread.php?t=1502829

0821 is the ls3 heads with light valves, 0823 is the l76/l92 heads. Same head design with heavier valves. They can be had a little cheaper usually.

Just keep in mind cam selection changes totally with the rectangle port heads. Your going to need 8 to 12 degrees split between the exhaust and intake duration because of how much more the intake side flows compared to the exhaust.

nahh didnt hijack it..............terrorist...... jk haha

Lol.


The cam I'm running is just a little more aggressive than the one that guy with the C6 is running (.600in lift and right at .100 PTVC). Also, I'm running an SD tune (gotta keep the 93 thing going lol), and a K&N 98-02 FIPK with my Ultra Z hood. Honestly, at this point, I can't justify throwing the $1k weight reduction mod to my bank account for a FAST intake setup (I'm going to continue to look elsewhere for power until I "NEED" it).

Your going to need 8 to 12 degrees split between the exhaust and intake duration

Agreed, mine is a 12* split

hmm i hear ya, ill have to do some reading on the ls3 heads for flow #'s.

the engine will be ripped down anyways im fine with fly cutting the pistons, no big thang there. whats the numbers on your ls3 heads for reference (i.e. ls1 "243" heads) ?

My GMPP catalog says:

intake:

.200 151
.300 208
.400 256
.500 294
.600 316

exhaust:

.200 111
.300 152
.400 174
.500 183
.600 189

Data based on a 4 in bore

edited: for stupid thought at first,, i see fast makes an intake for the l92 head

the other corvette build thread i see he never got it dynoed yet.

I must have mixed threads up. I appolagize.

From the flow numbers posted, it looks like if the exhaust port was worked over quite a bit, and the intake just de flashed, you could probably run a traditional split cam and make killer power.

I must have mixed threads up. I appolagize.

From the flow numbers posted, it looks like if the exhaust port was worked over quite a bit, and the intake just de flashed, you could probably run a traditional split cam and make killer power.

Even on a stock un-touched head it would make sense for more duration on the exhaust side to crutch the lower flow numbers in comparison to the intake.

By traditional I ment closer split as opposed to 12 degrees. Unless your exhaust flows better than your intake, there is no reason for a reverse split cam.

Oh got ya, I read that backwards, lol. I was agreeing with you on more exhaust duration, I'm running 12* more on the exhaust side.

I was getting at if you open the exhaust up, you could add more duration to the exhaust lobe, thus decreasing the total split.

Do you mean if you open up the exhaust port, you could add more intake (or use less exhaust) duration and decrease the total split?

Sorry man. Yes, less duration on the exhaust to even the split. It's been a long night at work. Lol

anyone else have any input or build or experience with a same targeted goal?

If I were you I would look at trickflow 225's. Flow better everywhere compared to a stock ls3 setup with more velocity. It is an expensive head but if you are looking at this kind of power you will need it.

my lq9 made 465/435 with stock runner 243's so i'd say 500 is very possible

You do not need an expensive pair of trick flows to make 500 HP at the wheels.

I have close to the same goal. Using a l92. Had pat g spec a cam and sending the heads out for porting when I receive my springs

trickflow 225's lookin about 2300
cnc ported and polished l92 head with better flow # over stock 1600
stock l92 600-900


thats what ive seen so far, havent got all 3 flow numbers side by side yet.


im planning on pat g spec'd cam also pokin around looking at the FAST 92 or 102 intakes, along with throttle body

does anyone know, im sure you can but... you can use a cable controlled TB on the intake you dont have to have electronic?

Yes. If you use the ls3 top end, you have to get a 4 bolt style cable tb. However, if you do get a fast intake, your stuck with the 102 as they didn't make a 92 mm fast for ls3 heads.

In my build, I'm going with a stock ls3 intake, maybe have it ported for now. I can't afford the fast right now and I'm creeping up on 5 years without my car running and a can't take it anymore.

Sorry maybe I missed something, is this a race car? cathedral port vs ls3 heads have been beaten to death.There is way more to a good cylinder head than just flow #s.

A good set of heads with a matching cam is the key. A set of stock ls3 heads with a matching cam will make the 500 he is looking for without shelling out big bucks for a set of cathedral trick flows.

It doesn't matter if it's a race car or not, bottom line is, best bang for the buck is the ls3 top end.

I'm not saying its not a viable option, ls3 setups do put out great peak numbers.....

I agree, and they put out great numbers across the board with the correct cam. They are reasonably cheap and in stock form can support a lot of power.

A good set of heads with a matching cam is the key. A set of stock ls3 heads with a matching cam will make the 500 he is looking for without shelling out big bucks for a set of cathedral trick flows.

It doesn't matter if it's a race car or not, bottom line is, best bang for the buck is the ls3 top end.

I agree, and they put out great numbers across the board with the correct cam. They are reasonably cheap and in stock form can support a lot of power.

Very true. I chose the LS3s and the stock rebuilt bottom end for bang for the buck reasons. With a few well chosen parts these setups will run hard.

not a race car......just a nasty street car.

for the record aftermarket heads arent out of my question, i want whats going to perform the best and give me power of what im looking for

so by all means anyone having info or using aftermarket heads let me know what you have and what you think

im shooting for minimum of 500 to the wheels not juuust to squeak to it or fall shy of it

Impressive for such a small cam.

http://ls1tech.com/forums/generation-iii-internal-engine/1327224-l92-heads-off-afr-230-v2-heads-504rwhp-6-0l-automatic.html

Very impressive...

But I'm not sure if your trying to prove a point or just adding to the info pool...looks like a combination of both. Good find BTW, that is a good thread proving cathedral port heads are still in the same ballpark.

I do however disagree with the direction of that thread. It tends to lead people to believe the l92 style heads are junk...

It is not hard to believe, going from a stock l76 to aftermarket heads, ported aftermarket intake and a cam that It picked up over 100 horse.

However, I am still a firm believer that the same power could have been obtained by milling the l92 heads, adding a matching cam and a good intake.

Not saying the ls3 style heads are near as good as the afr's, but with a cam to take full advantage of the large, lazy intake port of the l92 heads, massive amounts of power can be made.

I think where a lot of people become confused, is that the rectangle port heads are totally different animals than the cathedral port heads. They move air in a totally different manner and at different velocities. That's why I say with a good cam, ground to take advantage of the large amounts of air coming in at a relatively slow speed, can be just as effective as a head that flows less or equal amounts at a higher speed.

Good debate either way, I am having fun with this one. Hard to come across one where people don't get all sandy and pissed off because of 2 different opinions.

That is totally true, it would have been a much better comparison if the l92 setup would have been fully optimized before the swap.

Both setups will make great power as long as the rest of the combination is correct. I'm defiantly not saying that the ls3 style (rectangular port) heads are junk.

Before the ls world I came from SBC and BBC where everything is big rectangular runnered 420+ cfm, and guys are making huge power with these setups and they DEFIANTLY work.

For 500 rwhp both combinations could be easily optimized for that goal. In making that goal both have there advantages and disadvantages. With the l92 one advantage clearly being cost.

I just feel that for a street car a cathedral head has better driveability vs a rectangular port combo. What the op needs to decide is what are his real goals with his car (500 rwhp dont mean squat sometimes) and how much money does he have to spend?

Dont worry Bww people will eventually come in here and ruin this informative thread.:bang:

You know, at the same time, I have heard the rectangular port heads put up better driveability simply because the incoming air does not have to be moving at an incredible rate of speed to provide optimum performance...

Hmm, no I haven't heard that. If you dont mind me asking where did you hear this? I'd wouldn't mind hearing about that, definitively sounds interesting.

does anyone read my posts? (OP) hahahaha

Buy an LY6 which already has the L92/LS3 heads, Fast intake, and a Pat G cam. Remove the heads and have them shaved to up the compression and have them ported. That should put you in range.

BTW, an Lq9 is a Gen 3 engine so you would find more responses in that section.

collectively ive done about 3 hours of reading and searchin around for someone who has done a build close to what i want to do and cant find much.

last week i almost bought an ls6 shortblock to build but then i started kickin around the idea of a lq9..... then i started searchin and cant really find anything to impressive yet

my goal is to make atleast 500rwhp. id be happy at 500 but theres nothing wrong with a little more

but cant decide between a ls6 or lq9 only from what ive seen so far,

id figure a lq9 with a big ol' cam either shelf cam or spec'd out from pat g or so, along with a ported FAST intake AFR 215 or 230 heads with a small combustion champers pulleys throttle body to match the FAST long tubed and full exhuast....of course ARP all around and big injectors maybe some different pistons



are you just not going to see 500rwhp with that or not? all i can find is people using stock heads and such

would a lq9 have to be stroked or bored or both to see these numbers?

or is it gonna be the same as doing all the same mods to an ls6 with give or take 20-30 hp ?
Defiantly do the lq9 over the ls6. Cubic inch will be your friend in meeting this goal.(not that it cant be done with a ls6)

The hp over the 346 will not be any thing huge but torque will be up quite a bit, and every little bit helps if you dont want to be disappointed in the end.
I would run the stock bottom end if I were you, but you could do a cheap rebuild with scat rods and a good piston.

LQ9 here. Ported heads, small 226 cam and 2800 comverter. 7.20s @ 96 in the 1/8th at 3700+ lbs.

yes thats why im researching lq9s because i want to go bigger and figured itd be easier to make what i want to make to the wheels out of an lq9 instead of a ls6

and the lq9 gives me room to grow later. (i.e. stroker and or bored or boosted or blown)

for the record i dont mind about paying 2000 for aftermarket heads, thats why i made this post to find out whats gonna yeild best results without parts almost being at their limits.

was hoping for input from people with aftermarket heads and such what results, and also opinions on what brand or size head is going to be the best choice

yes thats why im researching lq9s because i want to go bigger and figured itd be easier to make what i want to make to the wheels out of an lq9 instead of a ls6

and the lq9 gives me room to grow later. (i.e. stroker and or bored or boosted or blown)

for the record i dont mind about paying 2000 for aftermarket heads, thats why i made this post to find out whats gonna yeild best results without parts almost being at their limits.

was hoping for input from people with aftermarket heads and such what results, and also opinions on what brand or size head is going to be the best choice

From the research that I have done on aftermarket cathedral heads they are all basically the same. Some have a little better midrange or top end than others but we are talking very minimal differences here. For a 364 I would look at anything 215cc-235cc runner depending on how wild it is. AFR, TFS, PRC, ETP are all great choices.

Well I can tell you that right now I'm putting together a forged lq with trickflow 225s, yellow tera rockers, fast 92/92, 230/238 .618/.618, 11:1 underdrive pulley, kooks 1 3/4, 42 lb injectors, ect.

This is going into a true daily street car 3700 lbs hence the smaller cam for power under the curve.
Car has a A4 3600 stall so I'm not looking for a huge dyno number here(If I had to guess I'd say 460-480 on a dynojet), but my real goal is to dip into the 10's and possibly 9's later on spray.:devil:

I feel that cylinder head is one of the most over looked items in a build because of the cost associated with it, but if you want a good running setup this is not a place that you want to skimp on. A good cylinder head is where most of the power is at.

You should read this if you haven't already.The thread is fairly old so its much easier to do now with the bigger intakes and better deigned heads, but a great read none the less.:corn:
http://ls1tech.com/forums/generation-iii-internal-engine/732392-recipe-500-rwhp-heads-cam.html

I dont know about the rest of the ls world, but (at least according to ls1gto) the record holder for ls3/l92 heads with a stock 6.0 bottom end is 487 rwhp.... so I would expect you're going to fall somewhat short of your goal with them. Im not knocking on ls3 heads though...500rwhp with a 6.0 bottom is going to be difficult regardless. OP, if you make 500+, you're going to be squeaking it out

for the record i dont mind about paying 2000 for aftermarket heads, thats why i made this post to find out whats gonna yeild best results without parts almost being at their limits.

What about having a set of GM heads hand ported?

You won't get the best results with a set of CNC'd heads that anyone else can get. Those heads are based off a port someone did by hand, and chances are that head porter kept plenty of tricks up his sleeve or has learned some new tricks since making that port.

Here are a few recommendations:
Greg Good
Curtis Boggs
Ed Curtis
Dennis Wheet

I feel that cylinder head is one of the most over looked items in a build because of the cost associated with it, but if you want a good running setup this is not a place that you want to skimp on. A good cylinder head is where most of the power is at.



i agree 100%, many people over look it

stroking the engine isnt out of the question, just was going to see what # i could possibly make without a stroker..... i guess not too many people have built these engines, i thought there would be more build references.

Building a lq9 is no different than building a ls2. Hop on ls1gto.com and theres a plethora of na 6.0 builds. The majority of them fall short of 500rwhp

O intsresting,boggins,I just found a few lq9's on here makin a little over 500 to the wheels with stock bottom end and ls3 heads.......id like input from experience internet forum hopping doesn't warrent that. Thanks to everyone with good input so far

O intsresting,boggins,I just found a few lq9's on here makin a little over 500 to the wheels with stock bottom end and ls3 heads.......id like input from experience internet forum hopping doesn't warrent that. Thanks to everyone with good input so far

I only suggested stopping by ls1gto since you're talking about building a stock bottom-end 6 liter, and that's what the majority of GTO's had, so there's a lot of knowledge over there directly pertinent to what you're looking for.

I never said there weren't stock bottom-end LQ9's making over 500 to the wheels... but whether they have square port heads, or cathedral port heads, I think you're going to find perhaps 10% of stock bottom-end (all motor) 6 liter's make 500+hp, and 90% make less than 500hp, unless of course you're running race gas.

You said yourself:


im shooting for minimum of 500 to the wheels not juuust to squeak to it or fall shy of it

Building a 6 liter engine that has a stock bottom-end, can run on pump gas, and makes north of 500rwhp without a power-adder is going to be difficult, and certainly you're going to end up "squeaking by" 500. If you add more cubes it's a whole different ball game, but that's not stock bottom-end.

l92 intake is dyno proven to make about 10 hp over ls3 intake. l92 intake can still be ported to get a few hp more.

ls3 heads best bang for buck and if you want a combo to build on and expand on such as a stroker in the future and dont mind spending extra money on $2-2300 heads, it would be cheaper to just go ahead and get stroker kit and use ls3 heads to begin with and be happier :) for less $.

some to think about.

i got lq9 and ls3 heads. self porting my l92 intake to use with fast 92 tb. looking at using eps 226-234, 598-602, 113+4 cam which pat g recommended. will be using harlan sharp trunion upgraded rockers and lighter ti reatiners. headers and all bolt ons. to go in a 72 nova project. unfortunately, lost my job, so project is on hold but in mean time porting my intake and then plan to work on the ls3 heads exhaust to improve flow. hoping for 465-475hp which should be plenty for the nova :)