I have a 2007.5 chevy 2500hd with the. 6.0 (ly6 i'm guessing? Instead of lq4) im looking for header flanges but I thought they would be rectangular but I was told they weren't so does anyone know exactly what heads I have and what exhaust header flange I can use for my truck? And does anyone know if the engine is considered gen IV or gen V ?

 

quick search on this forum turned up this information......

Well its pretty simple. The first V8 GM made, the 265, was the first generation of V8's or Gen I. The motors are long lived and lasted in trucks to 2000 with the Vortec 350 5.7L. The second generation was the Gen II or LT1 and LT4. Same basic design of the Gen I but had a front mount dizz and cam driven water pump among others.
So that leads up to 1997 and the introduction of the third generation of V8's or Gen III. The totally new designed LS1 5.7L! It lasted from 1997-2007.
The Gen III production run wasn't as long as the Gen I but has seen millions of motors produced. Mainly the workhorse LM7 5.3L and variants. Most swap motors used are Gen III but as production and time tells. Alot more Gen IV's are making it into swaps. And as the Gen IV get cheaper more and more will be available to everyone. The Gen IV motors started with the LS2 in 2005 and the LH6 5.3L in the Trailblazers it had AFM. The Gen IV trickled into the GM line up first appearing in the Trucks in 2007 GMT-900 platform With the LC9 5.3L, L76 6.0L, LY6 6.0L, and L92 6.2L.

Rumor's abound about the fifth generation or Gen V V8's. These include direct injection, and even OHC's. Only time will tell!



The Gen III/IV cylinder block shares two key design elements with GM's original small block V-8: a 90-degree cylinder angle with 4.4 inch bore centers. Beyond that, the latest small block applies design, casting and machining technologies that were unfathomable in the 1950s.

So whats the difference between the Gen III and Gen IV?
And why aren't they the same?
They look the same right?
Well yes and no.
The Gen IV was different enough for GM to make it its own generation. GM need to redesign the block and move sensor around to support several new technologies.

The Gen IV differences vs Gen III
•58x relutor wheel (crank trigger)
•Front mounted 4x Cam sensor (mounted on timing cover)
•VVT (variable Valve Timing) Oil operated cam phaser on front of cam sprocket
•AFM (Active Fuel Management) Deactivates 4 cly to improve MPG
•Side of block mounted Knock sensors
•Enhanced ECM's with separate TCM for the transmission.
•Returnless Fuel Injection with Stainless Steel Fuel Rail
•Advanced DBW with no TAC box needed


Gen IV Cylinder Block

The Gen IV block debuted in 2005 as the foundation for the 400-hp LS2 V-8 in the Chevrolet Corvette, and Pontiac GTO and the Cadillac CTS-v in 2006. Its deep-skirt design helps maximize strength and minimize vibration. The bulkheads accommodate six-bolt, cross-bolted main-bearing caps that limit crank flex and stiffen the engine's structure. A structural oil pan further stiffens the powertrain. The Gen IV aluminum block is cast from A356-T6 alloy, with cast-in iron cylinder liners. It weighs roughly 100 lbs. less than a comparable cast-iron engine block.

The new-generation small block is cast with oil ports in its V, or valley, to accommodate advanced technologies in the Vortec 5.3L and 6.0L L76, including Active Fuel Management (AFM) cylinder deactivation. The Lifter Oil Manifold Assembly (LOMA), a key component of AFM, installs in the valley in place of a conventional engine block cover. As a result, knock sensors located in the valley on the Gen III V-8 have been moved to the outside of the engine block, while the cam sensor has been moved from the rear of the block to the front cover.

#2 is knock sensor one on each side


Front timing cover with Cam sensor


Originally Posted by 1FastBrick
Here is what I have found. I tweaked it a little with help from others like trever1t
https://ls1tech.com/forums/new-ls...casting-s.html
CamaroZ28.Com Message Board


ALL Gen III heads are interchangable. How ever, They need to be matched up with the proper engine combo to see any gains.


Here is a list of a known production casting #'s:

933 97 aluminum perimeter bolt 5.7
806 97-98 aluminum perimeter bolt 5.7
853 99-00 aluminum center bolt 5.7
241 01-03 aluminum center bolt 5.7 (some late MY00 cars got 241 castings)
243 04 up LS6 aluminum center bolt 5.7 ***These castings were also used around 05 in truck applications***
862 99 and up 4.8-5.3 Truck heads
706 99 and up 4.8-5.3 Truck heads
799 05 and up 4.8-5.3Truck heads ***reportedly came on a few corvette's too*** These are basically 243 Heads
873 99-00 LQ4 6.0 Iron center bolt heads
317 01 and up LQ4 and LQ9 6.0 aluminum center bolt heads
035 01 - 04 LQ9 6.0 aluminum center bolt heads

Even more detailed info:

Casting Numbers 241, 806, 853
Head: 1997+ LS1 5.7 Liter Passenger Car
Material: Aluminimum
Part Number:
12559806 (1997-98) Chambers = 69cc
12559853 (1999-00)
12564241 (2000-03)
Combustion Chamber Volume: 66.67cc
Compression Ratio: 10.1:1
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

Stock Head Flow Numbers
Chamber 66.67 cc------0.100--0.200---0.300---0.400---0.500---0.550--0.600
Intake 200 cc------------67----122-----178-----215-----219-----223---227
Exhaust 70 cc------------52-----97-----133-----156-----170-----76----180


What you need to know:
The standard issue LS1 heads is best all-around head for the street / strip engines . A thorough porting and millimg job plus a valve upgrade on these will really wake up your engine.The heads have undergone only minor revisions since their introduction in 1997 , most notably a switch from perimeter to center valvcover bolt configuration for the 1999 model year. Each style has its own dedicated valvecovers and coilpacks mounting apparatus.



Casting Number 243
Head: 2001 LS6 5.7 Liter Passenger Car
Material: Aluminimum
Part Number:
12564243
Combustion Chamber Volume: 64.45cc
Compression Ratio: 10.5:1
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

Stock Head Flow Numbers
Chamber 64.45 cc-------0.100---0.200--0.300--0.400---0.500---0.550---0.600
Intake 210 cc------------62------126----184----224-----251----256----257
Exhaust 75 cc------------57------108----143----163-----176----180----183


What you need to know:
The LS6 cylinder heads is essentially a tuned-up version of the LS1 head. At 65cc, the combustion chamber is slightly smaller and more efficient than the LS1. The more efficient design shortens burn times and ultimately means less ignition timing advance is required to produce the same power. And because less timing allows more efficient combustion, the Ls6 heads allow the engine to produce more torque. The exhaust port is a unique D-shape that improves flow. LS6 heads are the best choice only when all-out power is needed. Be prepared for a big price tag at the dealer or steep core charge from your head porter.



Casting Number 706 and 862
Head: 1999+ 4.8L / 5.3 Liter Truck
Material: Aluminimum
Part Number:
12559862
12561706
Combustion Chamber Volume: 61.15cc
Compression Ratio: 9.5:1
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 1.89 inches
Exhaust Valve Diameter: 1.55 inches

Stock Head Flow Numbers
Chamber 61.15 cc----0.100--0.200--0.300-- 0.400--0.500---0.550---0.600
Intake 200 cc----------63 ---128----179-----210----218----221-----226
Exhaust 70 cc----------54 -- 93 ----121----145-----163----168----174


What you need to know:
These small combustion chamber truck heads offer no advantage over an LS1 head except the smaller combustion chamber. This along with milling of the deck surface will allow a slightly higher compression ratio to be achieved. Because of the smaller intake valve installed in these heads a valve upgrade is practically mandatory.

 

Casting Number 873
Head: 1999-2000 LQ4 6.0 Liter Truck
Material: ***Cast Iron***
Part Number:
12561873
Combustion Chamber Volume: 71.06cc
Compression Ratio: 9.5:1
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

Casting Number 317, 035
Head: 2001+ LQ4 and LQ9 6.0 Liter Truck
Material: Aluminimum
Part Number:
12562317 -LQ4
12572317 -LQ9
12572035 -LQ9
Combustion Chamber Volume: 71.06cc
Compression Ratio: 10:1 LQ9 Flat top pistons
Compression Ratio: 9.6:1 LQ4 Dish piston
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

Stock Head Flow Numbers
Chamber 71.06cc----0.100---0.200--0.300--0.400--0.500--0.550--0.600
Intake 210cc-----------66-----142-----196---228----236---238-----240
Exhaust 75cc----------59-----104-----137---155----167---173-----177



What you need to know:
The LQ4 head received aluminum heads starting in models year 2001. All other features are the same as previous years iron heads. This is the workhorse head for street / strip turbo and blower cars. They offer a large combustion chamber that lowers compression ratio making them perfect for a forced induction application. Swapping on the LQ4 head drops the compression ratio of a typical LS1 engine to 9:5.1
The Cast-iron casting are heavy!

So you want to figure out how much to mill:

It takes about .005" milling of the block deck to remove 1cc of volume. It takes .007" milling to remove 1cc from an LS1 head

Simple Milling Math:

You have a stock 66cc chamber and you want to get down to 63cc

66-63 = 3. You have to remove 3cc's

.007 x 3 = .021. So to get your 66cc chambers down to 63cc you'd have to mill ~.021.

You can also do the reverse, say you want to mill a head .030 to figure out how many CC's that removes you take .030 / .007 = ~ 4.28. Milling a stock 5.7 head .030 puts your chamber at ~ 62.



241 cast heads were Die Cast which is a process that smooths up the ports a bit compared to the Sand Cast procedure that was done on the 806 and 853 heads. Once ported any "advantage" the 241 cast had is moot.

Same Info applies to the:
4.8L/5.3L Truck 862 and 706 Head castings
While the 706 Heads are a SPM = Semi Permanent-mold And considerd to be a more consistant head casting then the 862 wich are Sand cast, Once ported There Is no difference.

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799 Vs. 243 Info Copied From pillboxesghost Post's in ths thread https://ls1tech.com/forums/conver...l#post10241473

This appears to be one of the common misconceptions about heads having the 243 casting no. -- they are not necessarily LS6 head assemblies. The LS2 heads (243 or 799 casting) have the "heavy" standard LS1 valves. However, they do have the LS6 springs.

Only the true LS6 engine heads have stainless steel (not titanium) hollow stem valves (the exhaust stems are sodium filled). These valves are slightly longer than LS1 valves too.

The LS7 heads do have titanium valves.

New LS2 heads are about half the price of new LS6 heads (check sdparts.com). GM is "really proud" of those hollow stem valves!

Oh, if you have the 799 castings -- the only thing "Corvette" about them is the valve springs/retainers! Still a desirable set of LS1 heads though!

Supposedly, the 243 mold was done at GM Research, the 799 mold furnished to other vendors. The same vendor may have the 243 and 799 mold.

Both heads have identical sized intake and exhaust valves

 

to answer your question in short form, any ls series header will bolt to your current heads. the exhaust ports and header bolt patterns are all the same.