Generation III Internal Engine - 799 casting 4.8/5.3 truck heads.




View Full Version : 799 casting 4.8/5.3 truck heads.


wht97ws6ta
05-03-2009, 02:27 PM
Has anyone messed with any of these yet. I just recently got my hands on a 5.3 aluminum motor out of a 05 Z71. It was supposed to have had a rodbearing knock, but the bearings were fine. For some reason the pistons had a ton of carbon on them and a bunch of loose chunks in the cyls. Which im sure was the knock that was heard. But anyhow to cut to the chase. This thing come with 799 heads which looks just like an LS6 head as far as the chamber shape. It has 2.00/1.55 valves. I tooked one off and got it on the flowbench at work. As cast they went 275 @ .600 int and 198 on the exh. I did some port work and a 5 angle valve job and got it up to 313 on the intake with alot of airspeed on the shortside. The exhaust went 243, both at .600 lift. I still got some work to do on the intake. Im pretty sure i can get 325ish outta it. Soon as i get them done ima write the CNC program on them. I just thought that was pretty impressive numbers for a production head. Im planning to put a victor junior and a 750 holley on it with a cam to drop it in my 87 El Camino. Just wondering if anyone knew much about these heads and thought i would share what i have learned from them.


Ryan02SS
05-03-2009, 04:06 PM
The #799's are the same as the #243 LS6/2 heads. Standard 24N Stainless valves, 2.00I, 1.55E, 210cc intake runner. The come standard on the L33HO 5.3L and 07+ 5.3L's.
My 08 Sierra has the #799's.

w3s1c0a5t
05-03-2009, 04:29 PM
So these bolt up to an ls1 with no mods? and they = to an 243 casting?


SweetS10V8
05-03-2009, 06:06 PM
Yes..

w3s1c0a5t
05-04-2009, 05:37 PM
What all does the l33ho come in? i havent heard of it.

BORN2FLY
05-04-2009, 06:45 PM
5.3L, VIN B (8th digit, opt L33) comes in some 05+ Trucks

2004 (only) Chevy SSR, 2004+ Isuzu Ascender, 2004+ Buick Rainier, 2004+ GMC Truck Envoy XUV, 2004+ Chevy TrailBlazer EXT: 5.3L (VIN P, 8TH DIGIT)

w3s1c0a5t
05-05-2009, 03:18 AM
5.3L, VIN B (8th digit, opt L33) comes in some 05+ Trucks

2004 (only) Chevy SSR, 2004+ Isuzu Ascender, 2004+ Buick Rainier, 2004+ GMC Truck Envoy XUV, 2004+ Chevy TrailBlazer EXT: 5.3L (VIN P, 8TH DIGIT)

You are the man sir.

CodeRed2000SS
05-05-2009, 08:07 AM
well dang, i learn something everyday.

gjohnson
05-05-2009, 08:54 AM
I just picked up a L33 also. This was pulled from another thread.

Here ya go, I found this on GM powertrain.com.

RPO L33 FOR CHEVROLET SILVERADO AND GMC SIERRA
The Gen III Vortec 5300 is available in a new lighter, higher output variant optional on some 2005 Silverados and Sierras. RPO L33 will be introduced in short bed, extended cab versions of these pickups. The L33 features an aluminum engine block, new cylinder heads and a high-lift cam. Torque will increase, and horsepower is expected to exceed 300 in final production trim.

One of the L33’s distinguishing features is its engine block. As with the 2004 LM4 Vortec 5300, the L33’s foundation is a cast-aluminum block with pressed-in iron cylinder liners, similar to the block used for GM Powertrain’s LS1 and LS6 car V-8s. The L33 block is exceptionally light; as a result, a fully dressed L33 is 100 pounds lighter than cast iron-block Vortec 5300s (RPOs LM7 and L59).

The L33 takes its cylinder heads from the LS6. Originally developed for the Z06 Corvette, these heads improve airflow in and out of the engine. With their pent-roof combustions chambers and new flat top pistons (the pistons in other Gen III Vortec 5300s have a slight sump in the piston deck), the L33’s compression ratio increases from 9.5:1 to 9.9:1. This increase improves the engine’s volumetric efficiency yet still allows it to achieve full power with regular grade gasoline.

Finally, the L33 is equipped with a higher-lift camshaft. Maximum valve lift increases from 11.6 mm on the LM7 and L59 to 12.5 mm. The new cam and compression ratio are the primary sources of the L33’s increased horsepower.

The L33 camshaft and cylinder heads were developed in conjunction with the new Gen IV Vortec 5300 (RPO LH6). The design objective was more horsepower for customers who need it, without requiring a step up to the Vortec 6000 (and an increase in operational costs). RPO L33 expands GM Powertrain’s lineup of Vortec V8s and gives GM’s truck customers even more flexibility and choice.

The L33 Vortec 5300 will be built at Powertrain’s Romulus, Mich., engine plant. With its introduction, Powertrain will cease production of Vortec 5300 RPO LM4. The Buick Rainier, Chevrolet Trailblazer EXT and GMC Envoy XL, previously equipped with the LM4, will now be powered by the Gen IV Vortec 5300 with Displacement on Demand. The 2005 Chevrolet SSR will be powered by the new LS2 truck V-8.




They had the LM4.


2004 (only) Chevy SSR, 2004+ Isuzu Ascender, 2004+ Buick Rainier, 2004+ GMC Truck Envoy XUV, 2004+ Chevy TrailBlazer EXT: 5.3L (VIN P, 8TH DIGIT)

07silveradoZ71
01-18-2012, 12:31 PM
Ok so i'm bummed out that my truck didn't come with L33, but I have found a 07' (new body style) with 799 heads, but an iron block, dose this motor share the same pistons and camshaft as the L33? Also, the motor has a different throttle body and intake than mine ( looks like a better pice )

'02 WS6
01-18-2012, 01:01 PM
I ran 799s worked on by PRC/TSP, milled .030, 2.02/1.60 Ferrea valves, on my LS6 in my TA. They're currently on a 376ci making 500+ rwhp so the heads do have potential if in the right hands.

wildcamaro
01-18-2012, 02:28 PM
L33 engines come with flat top pistons and coated piston skirts and, floating pins...regular 5.3 have dishes...the l33 also has the newer style rods too. I just got an L33 for -$100 lol, but anyway when I pulled oil pan I was suprised to see that the stock rods look much nicer than my buddies eagle rods he bought for his stang...L33 is a great engine because you get just bout 10 to 1 comp, as well as the good ls6 heads, and you get the 80 pounds of weight savings over an iron block

SOMbitch
01-18-2012, 10:44 PM
LOL back from the dead...

I just happened by the OP's (Drew) work when he had done the first ports. I need to ask him if that motor made it into the El Camino......

6SPDN
01-29-2012, 05:01 PM
I am planning to get a hand on a set of 799 castings. Does AI have the power to CNC'D these things to potentially lay down 500RWHP?(with other mods of course)

99 Blue Bird
01-29-2012, 05:08 PM
I am planning to get a hand on a set of 799 castings. Does AI have the power to CNC'D these things to potentially lay down 500RWHP?(with other mods of course)

Do a search

remauto1187
01-29-2012, 06:22 PM
Do a search

This clown has way too much time on his hands....to make the effort to put down "do a search".... Probably as useless as tits on a boar!

Bo185
01-29-2012, 06:40 PM
The Gen IV 4.8l/5.3l 2007 up motors have the 799/243 heads. All 4.8's are iron blocks. 5.3L are a mix of iron and AL block. And all the 5.3L are flat tops now. Also both have a 87mm intakes and TB's.

I have even seen a GMT900 truck (2007-up) with one 799 on one side and a 243 on the other. On the same motor from GM.

Also the 2010 plus truck motors ALL have VVT save for the old 4.3L!

NemeSS
01-29-2012, 08:01 PM
I have an iron block 4.8 with flat top pistons, came equipped with 243 heads. But the truck/suv engines with 243/799 heads did not come equipped with hollow stem valves.
So they are not ls6 heads. Ls6 heads only came on ls6 5.7 engines and nothing else

Bo185
01-29-2012, 08:51 PM
I have an iron block 4.8 with flat top pistons, came equipped with 243 heads. But the truck/suv engines with 243/799 heads did not come equipped with hollow stem valves.
So they are not ls6 heads. Ls6 heads only came on ls6 5.7 engines and nothing else
All 4.8L are flat tops. The L33 and later Gen IV 5.3L uses the 4.8L pistons were the same part number at one time.

But correct on the heads, the truck 243's are not the LS6 heads exactly, just the same castings.

ZQ8LS1
02-11-2012, 09:51 PM
Good info !!

Thanx

wildcamaro
02-11-2012, 10:24 PM
Yea I found out that those 4.8/l33 were the same piston the hard way, I couldnt find any pistons rings for an L33...had to get the for a 4.8 that's when I saw it in the sealed power catalog. Here is a little equivalency chart lol

Triangle/SPM cast Z06 corvette 243s > GTO 243 = Truck 243/799 > LS1 241 > LS1 853 > LS1 806

All of the heads above are better than 6.0 317 and 5.3/4.8 706 heads unless you get work done to them or in 317 case N2O/FI motors

bjamick
02-29-2012, 12:35 PM
I just saw an L33 engine with 8th digit on vin is a "B" and it had 706 heads? wtf?

Joe69z28
03-01-2012, 11:56 AM
I just saw an L33 engine with 8th digit on vin is a "B" and it had 706 heads? wtf?

All the L33s I have seen have had 799s or 243s. Was the the block aluminum , maybe it was switched over to a LM7

spordee1
03-09-2012, 03:17 PM
I am thinking about parting a L33 out. Everyone says things are worth more in parts. Engine is still running, truck was hit in the front and totaled. Questions 1. 799 Heads 2. Coils 3. Camshaft 4. Pistons and Rods 5. TB and Intake 6. Lifters and Rockers 7. Valve Covers 8. Flexplate 9.Oil pan with parts. Thank you a head of time.

taman86
03-11-2012, 02:39 PM
i just came across a craigslist ad for 799 heads off of a 07 5.3 so i was gonna put a lil info up on here but everyone has beat me to it. at first i thought that the 799's came on some ls2's but apparently i was wrong. if you find a set of 799's jump on em since they are the same as 243's, just not paying for the casting number. the ones i have seen are by half if not more, unless the person selling them are smart and KNOW they are the same.

FAD2BLK93
12-08-2012, 09:50 AM
Back from the dead again guys... But here is the question. Since the casting is the same on these heads as the original LS6. But the valves are not hollow, how much of a benefit would the hollow sodiums be? Should i hold out for them? I can get these heads for 100 bucks a piece, but the original LS6 corvettes are going for 2-250$. Opinions?

KCS
12-08-2012, 10:26 AM
Back from the dead again guys... But here is the question. Since the casting is the same on these heads as the original LS6. But the valves are not hollow, how much of a benefit would the hollow sodiums be? Should i hold out for them? I can get these heads for 100 bucks a piece, but the original LS6 corvettes are going for 2-250$. Opinions?

The exhaust valves aren't that great, but the intake valves are if you know how to take advantage of them.

FAD2BLK93
12-08-2012, 02:46 PM
So i would guess that the lighter weight, and some better heat dissapation would be worth the extra price?

96capricemgr
12-08-2012, 04:42 PM
The lighter weight can be worthwhile if the cam and springs are chosen to take advantage of it.

You do know not all 243s have the fancy valves right?

FAD2BLK93
12-09-2012, 07:40 AM
Yes, i believe just the true Ls6 do. Correct? I just dont know if the lighter weight would really justify the price? I plan to go with the AI 243/799 package anyway. Some impressive gains to say the least!

96capricemgr
12-09-2012, 09:36 AM
I think it would depend on the cam selection and how high you want to rev. If you want a reliable setup to put miles on and not spin to the moon I doubt the hollow valves worth the premium price. But if you want to push things to the limit with maximum lift and lots of rpm they would help.