weircc

iTrader: (6)

ok so i bought a 6.0 out of a 04 2500 hd (lq4) and i have been reading for a couple of weeks and have decided im gonna buy a ls3 intake because the price is right compared to ls6 intake, now even know i gotta change heads i think i will be better off in long run, NOW here's my question i see everyone talking about the L92 heads and im wondering is the L92 the exact same as the 823, what am i missing...... are these even 2 different heads?? im a total newb and i have searched for this answer but haven't found what im looking for.the reason i ask is because of the price seems like when someone is selling l92's they are 700-900$ and the 823's are 500-700 but i could have swore i read this where same heads. any info would be great thanks.

93Z2871805

iTrader: (5)

12629063 are LS3 and 12629064 are L92. They are the exact same casting with the exception of the LS3 having hollow stem valves, they are also cheaper than the L92s for some reason. LS3s go for $630 a pair (new) and L92s go for $840 a pair (new). FWIW my LS3s have 0821 stamps.

weircc

iTrader: (6)

ok so next question is what to get??

OrangeGoat

I would go with the L92 heads. But they really are the same heads except the valves like 93 Z28 said.

MX6.0

Why would you choose the L92's then?

LS3 heads:
-cheaper price
-Better valve control

Unless the hollow LS3 valves have some durability issues that I don't know about..

weircc

iTrader: (6)

ls3 is the 823's correct im sorry for asking just trying to learn

Sy99T/A

iTrader: (34)

L92 head is 5364

OrangeGoat

I'm not a fan of hallow valves. And I have L92s

weircc

iTrader: (6)

my plan is to get the l92's, ls3 intake, with a nice cam and a tune to go with my lq4 and be done (FOR NOW) HEHEHE

MX6.0

LS3 is stamped with 0821

4doortypels

iTrader: (39)

gm technically refers to those heads as L92 rectangle port heads. from what i have seen out there, i have 821s on my ls2 (which are the hollow intake, and full stainless exhaust) my friends 2010 M6 2SS has 821s. I have had ported 823s (which is the stainless intake and forget the material for the exhaust valve)

however if you havent bought an intake i would suggest the car style l92 which your current map sensor (10mm)will go directly in and clip in over the ls3(11 mm) and you have to buy a new map and pigtail for a nice clean install, or ive seen people put 3/8 vinyl tubing around the map to take up the extra space and RTV around it.

LS3s will rev higher, and be more stable than the l92 heads, and since both valves are stainless, they will do better for FI or Nitrous apps... the l92 exhaust valve doesnt like the heat as much... and with an lq4, id deck the crap out of them, being an lq4 is a 9.4:1 motor if im not mistaken, i know the lq4s have dished pistons from the factory and most guys go boost on the lq4s and NA guys go lq9 (10.0:1) keep in mind the heavier pistons dont like the higher rpms especially for an exteneded period of time. but if you deck the heads you can bump up the compression

weircc

iTrader: (6)

i would rather go ls3's on the heads because they are cheaper but most of the ppl i have talked to recommended the l92's as far as the intake ls3 i can get new for cheap haven't even thought about map sensor's and what not. thanks for pointing that out i will defiantly do some more homework. the PO cut wiring harness at the plugs so im gonna have to get one made up regardless. i was defiantly gonna mill heads to boost compression. i have a 2nd gen camaro im putting this in i want it to run better than the new camaro's guess im just kinda thinking ls3 top end with mild cam in a car thats 700 pounds little should do just that. i wanna say thanks to all the guys on this forum for the info and keep up the good work i really enjoy reading and learning thanks

93Z2871805

iTrader: (5)

When people say "L92" they just mean rectangle ports that aren't LS7s. The L92 was released first so both the LS3 and L92 are referred to as "L92s" by some. It's like when you have to tell people who aren't knowledgeable about Gen III/IV engines that you have an iron 6.0 "LS1" in your car for them to understand what you're talking about (my neighbor is a real old-school guy, so he still looks at my LQ9 like its some kind of alien technology, lol). SLP sells take-off LS3 intake assemblies minus TB for dirt cheap.

K11PER

iTrader: (8)

I'm glad I read this thread, you guys cleared up some of my confusion between L92 and LS3 heads. I might as well go LS3 if I can get them for that cheap brand new here and pair it with the LS3 intake.

I'm assuming the same TSP 231/236 112LSA cam will work just fine