Alwhite00

iTrader: (1)

Ok, I am putting a 99 or 00 6.0 in a 67 Chevelle and am looking to replace the iron heads with some 317's - what CR will I be at? Can these heads be milled to bump up the CR? if they are milled does it affect the push rod length? intake fitment? I will be using the truck intake.

I am new at this LS stuff, I just would like a little more power if I can do it relatively easy before I screw it together for good.

Any advice is welcome.

LK

71K20chevy

They certainly can be milled but why? For the price of new heads and a mill, you could buy some 243 or 799 heads and bolt them right on (ok, 317 heads usually go for $150, figure $75-100 for mill. 243s cost around $400). Stock LQ4 has compression of 9.4:1, so you'd have to mill a good bit off to bump up compression, plus like you said intake and pushrod problems. Just my 2 cents.

Alwhite00

iTrader: (1)

just tossing some ideas out there. what did the 243's come on?

LK

71K20chevy

5.3's. Not sure if they were on 5.7's or not...but they flow the same as 317's so there is only power to be gained.

Alwhite00

iTrader: (1)

will the chamber size work with a 6.0?

LK

71K20chevy

Yes. However, 6.0 heads on a 5.3 will not work.

You could also consider L92 heads, except I think they have the same chamber size as the 317's. They do flow better on the top end though. They're rectangular port heads, so the truck intake would not work.

Global Warmer LQ4

iTrader: (1)

This is the first time I've heard of the intake alignment getting affected but I suppose it makes sense.

I'm actually still deliberating this exact same question. inexpensive 317's ported polished and milled? OR 799's with a port and polish?

a pair of used 317's go for $100-$200 and 799's are easily $350-$500.

My situation is little different because I purchased LS2 flat top pistons and rods so my compression is already 10:1 with 317's, a mill would bump it closer to 10.5:1.

Still thinking about what to do. It will be interesting to see what you finally decided.

I've started junk yard searching. Some yards will sell the 799's cheap cuz to them its just a used 5.3L head from an 05 chevy truck

71K20chevy

Usually intake problems don't start occurring until you start milling .040 or so off. Personally I think if he had 317's done...it'd be more work than it worth. You're looking at some good money to mill, port and polish. If I were in his position, I'd get the 243's and get them mildly P/P if he wants to.

Global Warmer LQ4

iTrader: (1)

what about a home port and polish? and he gets the heads milled to no greater than 0.030 at a shop?

If the 317's can be purchased cheap, a home port and polish with a mill might still be cheaper than stock 243's or 799's.

idk, I went to a yard and walked around looking at their GM inventory. They had a pile of aluminum 317's and 706 heads they were going to scrap after they had torn down the 5.3 and 4.8L engines that they were also going scrap. They do this to make way for new inventory. I was shocked. I will keep a heads up for 05+ 799's but I think I can get "junk" 317 inventory for around $50 a set of heads. Which is still more than they'd get for the aluminum weight.

Global Warmer LQ4

iTrader: (1)

This is from a different post here on LS1Tech. I can't find the original to post a link but I did cut and paste this to a word document. Its really good data to help decide what heads to get:

Compilments of 1fastbrick on performancetrucks.net
HAPPY READING:

GM Head Casting Info
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
http://web.camaross.com/forums/showthread.php?t=410492


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.

--------------------------------------------------------------------------------
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

jsmith564

I'm not trying to sway you in any way but if you decide to go 317's i have a set sitting around. PM me if you want em.

Alwhite00

iTrader: (1)

How about the 241's? Would that be a good upgrade? What would the CR be?

LK

blazerboy72

iTrader: (9)

Search on ebay for 4.8 or 5.3 heads. I bought a set on 799's a couple weeks ago for $100 shipped with 10k miles. They were listed as 4.8 heads but had a picture of the casting number.

Alwhite00

iTrader: (1)

Are the 241's not desireable? I have a lead on a decent pair. What is the difference between the 241 & 799?

LK

Global Warmer LQ4

iTrader: (1)

what?! Damn, thats a good price, you wanna sell em for $200?? lol Deals are out there. The yard I bought my LQ4 agreed to exchange for my iron heads plus some cash but I'm still waiting

Global Warmer LQ4

iTrader: (1)

241's heads on stock 5.7L LS1 engines

799's heads on 05+ 4.8L and 5.3L engines but are exactly them same as 243 [except for the valve material].

243 are 2001 LS6 engines which flow really well for stock heads.

799 = 243

from my post earlier which was from another post lol:

"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."

Alwhite00

iTrader: (1)

Will 241 heads clear everything? Pistons, etc. I can get a nice pr for 140.00

LK

Global Warmer LQ4

iTrader: (1)

That's about what my budget is for heads. I'm keeping a lookout for 799's at the junk yard. I'm not sure what mods [if any] you would need to do to put 241 heads on a 6.0L. 799's are the same as 243's and 799's go stock on 05'+ 4.8L/5.3L truck engines. 243's are stock on 5.7L LS6's

Long story short, they seem pretty interchangeable. But I would call a performance-minded machine shop and ask them to be 100% sure you're not missing a mod.

I would hold for 799's at a junk yard though...they flow much better and $140 isn't the greatest price.

Plus, going from 317's [which should be stock on your 6.0L] to 241's would increase the compression ratio [good] but the flow numbers are less [bad?].

Unless your 317's are damaged, I would keep those p/p and mill them or hold out for 799's.

799's flow better than 317's, 317's flow better than 241's

..my thoughts

Alwhite00

iTrader: (1)

I have a 99-00 6.0 with iron heads and that is why I am looking to change them.

LK

Global Warmer LQ4

iTrader: (1)

idk, maybe others think differently than me but for a little more, you might be able to come across some 799's at a junk yard that flow much better than 241's. Look for a 05+ truck with a 4.8L or 5.3L engine, 799's are stock on those.
The $ spent on making the 241's flow as well as 799 seems like it would be more than just buying good used 799's.