Armycraft

So i spent the last hour or so researching the difference in the heads on a ls6 and an ls4, they are both 243 heads, i found a set for sale for 100 bucks, off an ls4, however i cant find info on the heads, some people say they are exactly the same others say the ls4 heads have smaller valves.
If they are smaller valves do they need to be machined out to accept ls6 valves and springs. is it worht the 100 bucks to buy them or should i keep looking for some ls6 243 heads.

moeZ28

iTrader: (7)

If the casting number is 243 then the valves should be the same size.

codyvette

iTrader: (24)

Not worth it. Direct the seller my way. JK, buy them.

A.R. Shale Targa

iTrader: (2)

BUY THEM !!! thats a good deal for sure. The only difference with the LS6
heads are the lightweight hollow stem valves (which are .0236" longer) and
either the yellow or blue beehive springs for the .551/.547 Vette cam.
You can have them surfaced, a good valvejob, and put some Lunati, Brian
Tooley, or PRC dual springs on and you'll be all set for a hot cammed set up.

Armycraft

I know the vette had the sodium filled valves and what not, but i just remeber reading somewhere that the ls4 had smaller valves then the ls6 even though they were both 243 heads. irregardless im buying them!

Armycraft

So next question since its relevant, the guy said i can buy the whole ls4 for 500 bucks, can i use that rotating assembly for an ls1? i have a bare ls1 block that im building wondering if i could use the crank?

Exeodus

iTrader: (1)

I believe the LS4 has a 10MM shorter crank due to the transversal mounting on the engine.

1997trans-am

iTrader: (2)

Is there a preferred casting number for ls6 heads?

luigiandme

iTrader: (2)

First off, the whole thing about the smaller valves is complete BS. I'm pissed that the guy actually posted that false information all over the web and everyones believing it. He claims its got smaller valves because they put the 243's o a 5.3 Yet the 799 is the exact same head and those are found on 4.8s all over the country.

Also, the LS4 crankshaft is 13mm SHORTER. 3mm from the rear flexplate flange and 10mm from the front snout.

and there is no prefered ls6 head, you have to measure valves to figure out if its the true z06 243 heads.

Jimbo1367

Buy them. Great deal as stated. Send them to AI or TEA. If you send to TEA for Stg2, they replace the valves w/ 2.04" IIRC.

Armycraft

Well then for the matter of having the real information does anyone know spec differences between the 2? valves and springs? are they still a 2.0 intake and 1.55 exhaust?

A.R. Shale Targa

iTrader: (2)

I've never heard of any 243/799 heads having the 1.89 intake valve....I'm
more than certain that all are 2.0/1.55