Need to know the difference between the 799 and the 243 heads!
 

So my brother is building an ls1 for his truck and he needs some heads. We heard that the 799 and 243 heads are the same, but they're not! If they were then they wouldn't have different numbers... So what is the difference?

built different years..
look under the hood of some of the NNBS 4.8/5.3s.. driver side might have a 799 and the passenger side might have a 243..

So did they discontinue the 243? But they are identical to each other? My brother said he read somewhere that the 799 heads dont have the sodium filled valves but the 243's do?

the 243s are still being used on the 4.8/5.3s.. cant say ive seen a 799 lately.. so i dunno.

You're not talkin about having the two different heads at the same time on one engine are you?

These heads are the same thing. Same valves,chambers ect.. It is just casted in a diff place from the 243's SAME HEADS

the difference is the casting #

I have read that the 799 castings were of a lessor mfg quality, produced south of the border but I don't know if that is truth or heresay. IIRC some Corvette guys reported having one of each a few years back.

Hey thanks for the input guys! If anyone else has heard something else plz post. My bro is lookin at some 799's... He just wants to make sure.

Yep,,, some of the NNBS when they first started coming out the 4.8/5.3s had mixed casting numbers.. 243/799s
theres a few post on it if i remember right.

i belive i have a 799 on the drivers side and a 243 on the pasengers side