Gen3 Gen4 LS Vortec heads info

[Marky Dissod]

Researched GM LS / Vortec heads. Ignored LS1 LQ4 & LQ9 heads, LS9 & LSA heads, LS7 heads.
Two types of holy heads ('holy' is shorter for 'cathedral' than anything else I could think of):

12559862 / 12561706!: . . '99-up 4.8L / 5.3L:
61.15cc combustion, 200cc holy in- port, 70cc oval ex- port, 1.890" in- valve, 1.550" ex- valve
These 'Gen3 holy heads' were eventually phased out, superseded by ...

12564243 / 799: . . '05-up 4.8L & 5.3L ... '01-up LS6 5.7L ... '05-up LS2 6.0L ... '08-'13 LFA / LZ1 6.0L hybrid:
64.45cc combustion, 210cc holy in- port, 75cc D- ex- port, 2.000" in- valve, 1.550" ex- valve
(Could these heads be an upgrade for 6.2L engines with talented custom tuning? Methinks YES.)

Two types of rectangle heads (don't say 'square'):

partnumber / partnumber: . . most 6.0L (10.4:1 or less) & 6.2L (10.5:1)
70cc combustion, 257cc rectangle in- port, 87cc D- ex- port, 2.165˝ in- valve, 1.590˝ ex- valve

partnumber / partnumber: . . LS3 (10.7:1) & L99 (10.4:1) 6.2L
68cc combustion, 257cc rectangle in- port, 87cc D- ex- port, 2.165˝ in- valve, 1.590˝ ex- valve
These heads seem a safe upgrade for the 6.2L Vortec engines.

 

[j91z28d1]

upgrade might depend on what you're tyring to do. I doubt a Cathedral port on a 6.2 is going to make more hp up top. you might get more tq down low around town and pulling, maybe run 87 octane but the rec port head will be faster in a race on 6.2 engine?

there's a aftermarket head that might be worth mentioning. it's ls3 based head with ls7 raised intake ports, using ls7 intake and all. ls3 valvetrain. for about the price of dropping a old set of heads off to be cleaned up and refreshed.

again, depending on what you're after, I don't think these would be good low in tq heads since the truck intake would not fit it. only a short runner high rpm intake

 

[strutaeng]

What about CFM airflow at a varying, given lift?

That will help you match the heads to the cam (actually, I think it's the other way around, but you get the idea.)

Aftermarket heads have even higher CFM.

More CFM = 'Mo Powah

 

[Marky Dissod]

... doubt a Cathedral port on a 6.2L is going to make more hp up top.
Might get more tq down low around town and pulling, maybe run 87 octane ... but the rec port head will be faster in a race on 6.2L.

Up top, as in, OVER 5000RpM? Rectangle heads, no doubt.

What about CFM airflow at a varying, given lift?
That will help you match the heads to the cam (actually, I think it's the other way around, but you get the idea.)
Aftermarket heads have even higher CFM.
More CFM = 'Mo Powah

Again, PEAK horsepowah thinking - also, forgetting about compression.

Been reading up on Richard Holdener. Does he huff nitrous or Jokergas before taking a pic?
Anyway, between reading his writings, and studying the above OE data carefully ...

Thinking ahead to my replacement engine here, to be ready if/when mine fails.
Closest I get to racing, is reacting to the light turned green before duh-slo-mol-lasses.
I floor it all too often like a jerk, yet it's been weeks since I last saw 5000RpM,
my last WOT 1Up2 shift was months ago, can't remember my last WOT 2Up3 shift.
Actively disinterested in any more peak RpMs than the L59 already has.

IFF I upgrade from my intake manifold (maybe? or not?), as similar to the LS2-TBSS intake as possible.
Forced to settle for another 5.3L, no iron - aluminum block with an LS2-TBSS-type intake manifold.
If 6.0L, aluminum preferred, hope I can still afford an LS2-TBSS-trucky intake?
If 6.2L, selling the rectangle heads should cover the cost of an LS2-TBSS-trucky.
Obviously no V4 mode horseschidt. Don't forget: no VVT either.

I'll be ecstatic to make 370 horses @ 5000RpM on 87 octane.
The REAL goal is to improve MpGs.
Only thing left to do is a short list of 3 or 4 or 5 no-V4 no-VVT cams -
leave that for another thread though.

 

[swathdiver]

My 5.3 makes more torque down low than my 6.2s. If only for a few moments and then they rocket off into space! I too considered 243 heads for a 6.2 build but their heads flow so much better, you don't have to port/polish do bowl work until you are well over the 600 horses mark.

My 2013 6.2 Sierra puts down 372 horsepower to the rear wheels through the traps in the quarter mile. She's bone stock still.

Can't wait to see what BlackBear will unleash with a tune and raising the shift points past 5,800. The lifted 2012 keeps pulling like a freight train at 6,200 rpms.

 

[j91z28d1]

OK.. long ramble warning.

so Richard Holdener...nothing wrong with the guy. I've seen this guy's articles from the 90s when businesses would throw parts at these magazines writers for the advertising. picture long nights in a dyno trying to make a combo work in a way to put their parts in a good light. and then show that combo.

so you got a new high flow head, well you don't bolt the heads on a stock engine to show a performance gain. you put the stock heads in a big cam, big displacement, high compression engine. make a pull, swap on high flow heads. make pull, numbers go up.. parts sell. it's not dishonest in anyway, but it is a tad misleading. you have a part that's marketing low end tq, you bolt it on a reverse combo.

so he's got all these saved engine dyno charts from different combos tested over the years. he picks a subject for tonight's live and then shows the charts that back up what tonights story line is. all very interesting and entertaining. I've watched a few myself.


but the part that's a bit dishonest in my opinion...we all thing we are learning something special but none of that pertains to your real world driving experience. he's got an engine on a dyno stand, free flowing well tuned for Scavenging exhaust, no accessory load, aftermarket stand alone ecm that's targeting best air/fuel ratio for power and timing. 100 octane fuel to remove the variable of knocking and wot from whatever power band he wants to show you.. either 3k to 7k or 2500 to 6k. he is open and tells you all of this but if you don't understand how that pertains to your vehicle and driving style. you are left with almost completely useless information. say your combo, and I think you're wanting what 90% of us want out of our daily driver.

your stock exhaust is unturned for scavenging, you have tons of accessories on the front, your stock ecm is targeting 14.7:1 air/fuel. (to lean for power) anytime it's not in power enrichment mode(PE usually to rich for best power to be safe on the street) piss water 87 octane. and you're never or hardly ever at wot max load at say 2k rpm, and definitely not running out to 6k often.

so as you can guess, you can take the engine off his dyno stand that seems like it would be perfect for your driving style, bolt it in the truck and never hit the perimeters used during his testing. it's just not really relevant.

in my opinion, the transmission tune, and if it's 4 speed, 6 speed or new 10 speed, along with axle gearing has more effect on what you're trying to get from your truck than even 40hp or 40tq moved into a different rpm band on your truck. what you're looking for is throttle pedal mapping. the feel of it being eager to run at 1/4 throttle. in that way something like a pedal commander and a good tranny tune would go further towards your goals than anything you're going to be able to build using different heads.


I drive lots of ford's, fleet junk. but one thing I believe they do much better than gm is the throttle mapping. they always feel like they want to go. they tune their trucks that way where even a gm car that has sport mode will need to be turned to sport to feel that way. this I believe what sells on a test drive and really what we all want from our mods if we aren't going to drag strip or lineing up next to our friends for a little grudge march.

as for what you're looking for, I believe gm built basically that combo. the LFA they stuck in the hybrids I would hope is the more efficient combo for daily driving, cause gotta have a little faith in gm engineers haha. it's a aluminum 6.0, so lighter and smaller bore works better in theory to control detonation, allowing for your lower octane 87 than a 6.2 bore. (this is said to be why gm loved the 305ci in the 90s smog era, small bore better mixture inside the cyl during compression stroke) the Cathedral Port heads for higher speed airflow in the intake port at lower rpm(better filling). they also raised the compression, but mainly because of the cam they went with. late intake closing, it bleeds off a low of compression at low rpm, say idle to 1500 for a cleaner charge from there up. you wouldn't want this cam, it would feel super lazy, but not 100% sure you could run 87 in it with a normal cam on that higher compression. they cover for the lack of off idle tq by using electric motors, but even then the throttle map in the hybrid is more loft down the road on a magic carpet (cvt tranny keeps it at that stead efficient rpm while mph increase too) than race from light to light but something like that with a normal cam and compression, might get you the best hard parts for 87 octane and 2000 rpm tq at lean part throttle a/f, but it will all be in the tuning of making the throttle mapping feel right and the tranny keep you in that band just right.


so yeah.. in the end, it's best to keep the combo you have and do the longevity mods to make it last 300k than anything else. that and vvt is your friend, try and keep that active even if you build something new. they don't really fail and it's free tq.

 

[Marky Dissod]

I'd love a more precise definition of 'down low'? Not to mention, how much more torque?!?!?!
Suffice to say, bet it's where most of our engines spend most of their time.
is your VVT limited? Or did you disable VVT entirely?

Hard redline ceiling no higher than 6000RpM, like any 5.3L.
Don't want / need the 6.0L to peak power past 5700RpM.
With a 6.2L, an even lower peak power RpM would be PREFERABLE.
Trying to make a slightly-higher compression, yet still truckier truck engine.
Need to find accurate LOW-lift flow numbers ...

 

[Marky Dissod]

My mistake, posting in the GMT900 subforum. See my sig.
Any mod who thinks this'd be better off in the GMT800 forum, feel free to move it.

But j91z28d1 has the idea. I'm accustomed to the mid '90s LT1.
Quick snappy throttle response from 10:1 compression w/ 87 octane.
Party's over by 5400RpM, which protects both engine and 4L60E.
I've also L98 memories, not quite as quick throttle response,
but even more low-end due to the TPI manifold.

Yes, I think 2 out of 3 of us would prefer more of the powerband sooner.

 

[swathdiver]

I'd love a more precise definition of 'down low'? Not to mention, how much more torque?!?!?!
Suffice to say, bet it's where most of our engines spend most of their time.
is your VVT limited? Or did you disable VVT entirely?

Hard redline ceiling no higher than 6000RpM, like any 5.3L.
Don't want / need the 6.0L to peak power past 5700RpM.
With a 6.2L, an even lower peak power RpM would be PREFERABLE.
Trying to make a slightly-higher compression, yet still truckier truck engine.
Need to find accurate LOW-lift flow numbers ...

From idle to about 1300 rpms at WOT before my 6.2 exceeds my 5.3 torque and horsepower numbers. At 1,296 rpms they are both making 66 horsepower and 268 foot pounds of torque. I recorded this data from each truck with the Tech-2 and then extrapolated (filled in) the data between points in an excel spreadsheet.

6.2s love to rev with those 823 heads. You'd get more torque down low with 243/799s and up to your 5700 peak probably.

My 6.2 example is bone stock, my 5.3 has been tuned but still shifts at 5800.

It just occurred to me, when those 6.2 numbers were taken, she was still running on KO2s which sapped the engine of over 50 horsepower due to all the extra rotational weight of the heavier tires. Hmm!

My mistake, posting in the GMT900 subforum. See my sig.
Any mod who thinks this'd be better off in the GMT800 forum, feel free to move it.

But j91z28d1 has the idea. I'm accustomed to the mid '90s LT1.
Quick snappy throttle response from 10:1 compression w/ 87 octane.
Party's over by 5400RpM, which protects both engine and 4L60E.
I've also L98 memories, not quite as quick throttle response,
but even more low-end due to the TPI manifold.

Yes, I think 2 out of 3 of us would prefer more of the powerband sooner.

Me too, I miss the off the line torque of our older cars, when they were rated at like 235 horses and a hundred or more foot pounds of torque more and they were all out of breath by 5400 rpms. BUT, these LSs exceed them in power and efficiency in every way.

 

[strutaeng]

How about a LS 383? Bore the 5.3 bore to LS1 bore diameter (I think?), 4" stroke crank, new pistons. No clearancing the block on the iron block version is what I've heard/read. I always hear the torque is pretty good on that combination. A stock 5.7 bore on an iron block is also an option.

I may decide to try to build one of those down the road, just for fun.

You'd have the low-end torque but if you wanted, but still have all the ponies under the skinny pedal, ready to be released.

I've wondered why the LS 5.7 was never installed on trucks in an iron block version, especially the heavier ones, but it's probably because they (GM) had the 6.0 under their sleeve.

Do you have a budget?

 

[Marky Dissod]

My budget is my biggest problem. Living in a NYC apt is problem number 2.
My idea was - IS - to see if I can mix and match GM parts better than GM.
Hence, holy port heads a 6.2L.
Not crazy enough to try 862 / 706 heads on any 6.2L, but they'd be great on any 6.0L.
The 6.2L can get 243 / 799 holy port heads instead of the 862 / 706.

 

[Marky Dissod]

@swathdiver,
the other thing I noticed about TYF is an aversion to more assertive axle(s) gearing.
You said
"when those 6.2 numbers were taken, she was still running on KO2s which sapped the engine of over 50 horsepower due to all the extra rotational weight of the heavier tires."
The engine made the same power. The ground never got it, the tall heavy tires dissipated it.

Had a Caprice wagon.
Top speed with 2.56: 130MpH. Took so long, I got worried about the engine.
Literally long-dragged a cigarette and exhaled it all between 129MpH & 130MpH.
Top speed with 3.42: 140MpH. Wish I'd timed it -
did not take nearly as long to 140MpH, as 2.56 did to 130MpH. I got scared @ 140MpH and let up.

Very rough math suggests that that axle upgrade was worth 60 horses, and more than 60 ftlb.

But if I make an engine with enough low-end, 3.73 will be just barely enough axle gear.

 

[swathdiver]

is your VVT limited? Or did you disable VVT entirely?

No VVT on the 2009 5.3 LC9 engine. Stock VVT setup all around on the 2013 6.2 L9H.

 

[j91z28d1]

My mistake, posting in the GMT900 subforum. See my sig.
Any mod who thinks this'd be better off in the GMT800 forum, feel free to move it.

But j91z28d1 has the idea. I'm accustomed to the mid '90s LT1.
Quick snappy throttle response from 10:1 compression w/ 87 octane.
Party's over by 5400RpM, which protects both engine and 4L60E.
I've also L98 memories, not quite as quick throttle response,
but even more low-end due to the TPI manifold.

Yes, I think 2 out of 3 of us would prefer more of the powerband sooner.

I read an article forever ago in a car and driver mag, I believe it was. back when having magazines sent to your house was a thing.. very enjoyable thing too. anyways, the lt1 was meant to be gm's world beater. they thru everything at that engine. reverse cooling for high compression, the opti spark was said to have such fine resolution, it could change timing 1 deg for each individual cyl and remember that offset. the timing strategy was meant to be able to run max timing in each cyl, not just a over all timing. because the old sbc loved timing. the more you could get in it, the faster it went. Sadly it was the down fall too and the end of the small block. they basically started with a clean sheet for the ls. it works, but I still feel had they just went coil packs, and had the lt4 heads be the standard head across the board it might have survived. it definitely had the grunt and a whole different sound. maybe a aluminum block too haha


man, you're taking me back.. the tpi days, still under rated to me. probably should have been a truck engine instead of a sports car engine, I've always wanted to put a tpi intake on my 96 tahoe 5.7 but you just can't tune the 96&97 black box ecm. I had a z28 tpi 305 with a old slp cam, no real tuning, it was a 5 speed car and ran 13.8 at the track at the same time the car world was falling all over the 93 lt1's running 14.0s. we had so much fun running around town racing everyone one of them we could find. no one would ever believe it *** a little 305. it just hooked hard, rowed gears at 4500rpm and held them off. never let them know it was done at 110 and they just got rolling around then haha.

still got a 90 formula sitting in the garage just begging for some time. right now it's got a 406 with a decent cam, some old school trick flow heads and scored a super ram going on 30 years ago now. was said to he ported by Lingenfelter long before accel bought them out. it's still a 5 speed car, only cause I haven't driven it enough to break it. t56 shoved in a corner for when it goes. now that things got the tq, big tb and cable throttle so nothing slows it down. wack the throttle in the first 2 gears and it feels alive, like it's got a soul my ls3 c6 just doesn't have. sadly the ls3 car would probably beat it even when I'm done and get it tuned right. but what can ya do haha.

 

[Geotrash]

I read an article forever ago in a car and driver mag, I believe it was. back when having magazines sent to your house was a thing.. very enjoyable thing too. anyways, the lt1 was meant to be gm's world beater. they thru everything at that engine. reverse cooling for high compression, the opti spark was said to have such fine resolution, it could change timing 1 deg for each individual cyl and remember that offset. the timing strategy was meant to be able to run max timing in each cyl, not just a over all timing. because the old sbc loved timing. the more you could get in it, the faster it went. Sadly it was the down fall too and the end of the small block. they basically started with a clean sheet for the ls. it works, but I still feel had they just went coil packs, and had the lt4 heads be the standard head across the board it might have survived. it definitely had the grunt and a whole different sound. maybe a aluminum block too haha


man, you're taking me back.. the tpi days, still under rated to me. probably should have been a truck engine instead of a sports car engine, I've always wanted to put a tpi intake on my 96 tahoe 5.7 but you just can't tune the 96&97 black box ecm. I had a z28 tpi 305 with a old slp cam, no real tuning, it was a 5 speed car and ran 13.8 at the track at the same time the car world was falling all over the 93 lt1's running 14.0s. we had so much fun running around town racing everyone one of them we could find. no one would ever believe it *** a little 305. it just hooked hard, rowed gears at 4500rpm and held them off. never let them know it was done at 110 and they just got rolling around then haha.

still got a 90 formula sitting in the garage just begging for some time. right now it's got a 406 with a decent cam, some old school trick flow heads and scored a super ram going on 30 years ago now. was said to he ported by Lingenfelter long before accel bought them out. it's still a 5 speed car, only cause I haven't driven it enough to break it. t56 shoved in a corner for when it goes. now that things got the tq, big tb and cable throttle so nothing slows it down. wack the throttle in the first 2 gears and it feels alive, like it's got a soul my ls3 c6 just doesn't have. sadly the ls3 car would probably beat it even when I'm done and get it tuned right. but what can ya do haha.

I think they took the ol' SBC as far as they could for performance and efficiency. It wouldn't have survived the kind of power we're seeing right out of the factory with the LS and now LT engines. 6 bolt main caps vs 4, the main caps bolt through the skirted block, stronger crank, bigger cam diameter means more valve lift with less shock to the valvetrain, and this is all before we even talk about the heads.

What I like most is that GM blew away the conventional wisdom of the time which said that a 2-valve pushrod design could never make the kind of power that a 4-valve DOHC design could. And yet, here we are. Simpler design than DOHC means easier to work on and better durability. Timing chain stretch is killing DOHC engines every day with half the miles of an LS on them.

 

[j91z28d1]

it's kinda all relative, and in theory cause I only know really what a read.

there was a hybrid block for a while, that was said to be the best of both worlds, it was a Gen 1 sbc bottom end using ls heads. it was pricey back we people didn't buy expensive parts like today and iron. back then everyone wanted the aluminum ls1 for swaps but it was said in a perfect world that was the setup.


depending on who you follow, some like the cross bolt mains of the ls, others say it's a m8 bolt, it ain't doing anything but leak oil where a 4 bolt main with splayed style make the bolts pull from the main webbing of the block.


there is something to the valvetrain of a ls, as much as I hate that you gotta pull the heads to replace them, most engine builders I've read about say you can get a away with a hydraulic lifter in a ls way longer than a sbc. you wanna make any rpm with the old school stuff just go solid they say.

the Gen 2 lt4 head is pretty comparable flow numbers with the old ls1 stuff. I think it would have heald it's own. bottom end of both are plenty strong for bolt on hot rodding around. if you wanna make big power like say a turbo e85 build, both really should be built off a aftermarket block and rotating assembly. and then at that point you pop head gaskets in the ls every other pass.

the fastest stick shift car right now is a gen 1 in a 4th Gen camaro. it's all race car so it hardly matters, but does show that 5 head bolts are better than 4 at some point. that point probably isn't na thou.

i currently have 2 of each, and if I gotta pick one to work on, I'd much rather work on a gen1.

 

[Marky Dissod]

Gonna try to pull this back toward the original topic, if y'all don't mind ...

Long story, medium, when the day comes to replace my engine,
It already has 12559862 or 12561706 heads, duhr.

Scenario 1 (how GM should've done every 6.0L, damnt):
If my replacement / upgrade engine is a 6.0L, it'll get my old 5.3L heads.
With luck it's a Gen4 aluminum 6.0L, likely equal to or better than an LQ9.
My guess:
A Gen4 6.0L with 862 / 706 heads'll make less peak power at a lower RpM vs OE.
If the rest of the powerband moves back to the left, I'll be happy.
Is there a better GM OE cam than the LS2 cam for this concept engine?

Scenario 2 (more of a risk):
If my replacement is a 6.2L, it'll get 12564243 / 799 heads.
12559862 / 12561706 would exceed 11.1 to 1 compression.
I'M FULLY AWARE THIS ABSOLUTELY REQUIRES CUSTOM PCM TUNING.
My guess:
A 6.2L with 243 / 799 heads'll also make less peak power at a lower RpM vs OE.
If the rest of the powerband moves back to the left, I'll be even happier.

Don't forget I'll be using a 12200411, so NO VVT either.
(I think VVT helps rectangle heads at very low RpM.)

How crazy does the above seem, really?

 

[j91z28d1]

do you currently have a 5.3?

do they still make that 5.3 stroker kit? that might be the most cost effective way to get where you want? you can pick the compression you want when you're changing pistons.

 

[Marky Dissod]

L59, yes.
RANT
GM first pist me the L off by making a 4.3L L99 V8 out of a 5.7L LT1 V8, instead of using the 4.3L L35 V6.
Then GM made 4.8L & 5.3L Vortec engines out of 5.7L LS1s, and I developed a chronic tick.
For decades, GM upgraded the 350 V8 for 'vettes & F-cars.
(Every great GM 5.0L is outnumbered by 1000 5.0Ls that could've been better by .7 more litres.)
Then GM makes a pretty damn good 5.7L, and de-bores it for trucks?
And then de-strokes the 5.3L they already de-bored, instead of improving the 4.3L V6 like they did the small-block just a few years ago?
I could've saved GM BILLIONS by simply lowering the LS1's redline for use in trucks.
I dream of a world, where every 4.8L & 5.3L, is a 5.7L that just needs a better cam & valvetrain. Then I wake up.
ANYWAY
I've no intention of re-stroking anything to restore what GM de-bored.
Bore makes more power than stroke anyway.
I'll live with yanking a Gen4 crank to swap a 58x crank reluctor for a 24x.

Obviously scenario 1 is cheaper ...

 

[Marky Dissod]

Just finished this video from Richard Holdener.

Under 4000RpM, where most of our engines spend most of their time,
guess which heads performed best on a cam'd 6.0L?

706-862-895 heads outperformed 243-799 heads. In other words:
Gen3 holy heads outperformed Gen4 holy heads ...
243-799 heads outperformed 716-364-823-821 heads. Or:
Gen4 holy heads outperformed Gen4 rectangle heads ...
UNDER 4000RpM, which I care about far more than 4000-5500RpM.