408Maro

iTrader: (14)

im a lil confused. arent the 243 casting ls6 heads? i see that they are also the same casting for ls2 heads. whats diffrent on the two?

NemeSS

iTrader: (127)

ls6 = sodium filled valves 243
ls2= regular valves
799 also same as 243 ls2

408Maro

iTrader: (14)

so they both will fit on the ls1 and ls2 blocks,same valve sizes and just diff type of valves, and 243 heads are also the 799 for ls2? so does the diff valves really make a big diffrence?? thanks

ROCNDAV

iTrader: (100)

so if they are all 243 heads, how does one differentiate the heads from each other? Yellow springs denote LS6 heads, but anybody could have replaced the springs. Can the valves be weighed? Is there a different part number on the casting?

LS6 were 3.898 bore where LS2 are 4.060, so do they both require the same size/bore head gasket if used on an LS1?

97ta383

iTrader: (5)

How would you tell if they are sodium filled valves? i just bought a set of what were siad to be ls6 243 heads and they have the yellow springs and yellow marks on the valves they are brand new.

NemeSS

iTrader: (127)

ls6 supposed to be fitted with yellow springs and the lite sodium filled valves, the valves themselves weigh less than a reg steel valve. the 243 casting itself is same for all.
799 is also same design as 243 as far as intake and exhaust ports, chambers.
ls2 were used on 4.00 bore, but chamber is same for all.
will need 4.00+ bore if using 243 on 4.00 block.

have to weigh the valves to verify if really ls6 version

408Maro

iTrader: (14)

So both can be used on either block either way? And there really is no BIG difference in the 2?

rpturbo

iTrader: (47)

Yes both can be used on either block either way, however according to the info I have read the sodium filled valves rev much higher much easier due to the weight, by comparison. Would you tell the difference in an average street car, I kind of doubt it, but would you see a difference on a side by side dyno.....probably.

krwyellowZ28

iTrader: (10)

Aren't the stock LS6 valve stems longer to make up for the smaller base circle LS6 cams? Wouldn't one need to use shorter pushrods to make up for this?

JonCR96Z

iTrader: (33)

To help clear this up. The bare head itself is the 243 casting, when they get cast they probably have no idea what valve is going into it. The 799 is the exact same design just cast at a different plant. So if there is a problem it can be more easily traced to the source. As far as flow numbers LS6 243s, LS2+ 243s and 799s should all be relatively the same.

The LS6 valve is .023" longer than the standard LS1 valve, I would assume that the LS2 uses the same valve as the LS1. Pushrods may to be longer or shorter for the best contact pattern, but it would depend more on the rest of the setup than the valves.

wickederz

iTrader: (1)

Did 2002 z28's come with 243 ls6 heads?

JonCR96Z

iTrader: (33)

Nope.

SOMbitch

iTrader: (8)

To clarify a little more:
LS6 Z06 243's had hollow intakes and sodium filled exhaust. Made from 01-04 IIRC. The sodium was in the exhaust valve to absorb the extra heat while the intake lowered weght and allowed the stock motor to redline at 6500.

Any other 243/799 casting had solid steel valves and are basicaly identical..

someday

LS2 heads r the same as the '01 LS6 heads, the '02+ LS6 heads had the sodium exhaust valves... LS2 cams were also the same as the '01 LS6

Mrls12000no2

if i put a stock ls2 cam and a pair of 243 heads how much power would i gain in my 2000 z28?

87silverbullet

iTrader: (11)

Congrats rookie on popping your cherry. You just replied to a 3 1/2 year old thread that was started 4 1/2 years ago.

To answer your question you would make about 380-390 crank hp. There are better cams out there so I wouldn't go thru the trouble of putting an LS2 cam in the motor.

Jimbo1367

LOL.

I always thought the 799 was always used for trucks and had a larger combustion chamber to lower trucks compression. I also assumed ( I know, mistake) this is why alot of people liked the 799 heads for turbo builds.

KCS

iTrader: (20)

You may be thinking of 317 castings with the 71cc chambers.