wolfy

iTrader: (1)

so, just in case, i did search...but all i got was 90% for sale section, and the rest didnt really help.

what are the difference in the casting #'s on ls1 heads? there are 853, 241, and 243 (i dont think im missing any, but feel free to school me...). what are the differences, and has anybody flowed all of them comparably and what were the results. as far as i know the 853's are the worst you could have, the 241's are the middle of the pack, and the 243's are the best you could have, all being stock...

also, just for the record, has anyone ported these heads and flowed them compared to stock, and what were the results.

sorry for the bonehead questions, but i had some questions, plus i thought it might be nice for some folks if all the info was compiled in one thread...who knows, maybe it might make a nice informative sticky...

thanks in advance for the info...

-cam

NviouSS

iTrader: (8)

some are 5.3 heads, some are 5.7 heads and some are 6.0 heads. just depends on the casting number. the ones you listed are 5.7 heads

camscam02

iTrader: (21)

853 heads came on 98 Ls1 cars and some 99's i bleieve
241 heads came on 99-02 Ls1 cars
243 heads are Ls6 heads that some on the ls6 motor!

feel free to correct me if im wrong!

orangeapeel

iTrader: (18)

Also 806 is the 98 and 317's are the 6.0l truck heads.

Studytime

iTrader: (15)

These are actually the correct numbers (I've owned a set of each except for 317 heads);

806 heads on the '98 Camaro
853 on the 99-00 cars
241 on the 01-02 cars

243s are LS6 heads
706 are 5.3/4.8L heads
317s are 6.0L heads

I'm pretty sure I got all of the major ones right.

If they're getting ported the casting number is not that important- especially among the 806/853/241 heads. If they're not getting ported, go with the LS6 heads.

Ben T.

GuitsBoy

iTrader: (4)

These are correct, but some late 2000 cars got 241's.

jetblast

the 243's have been casted in two different plants, one has a better method and are identified by looking for a v shaped line that looks almost like a weld, and is chevron is located just below the spark plug hole, straight from the ls6 gm performance book, my heads came with them and supposedly they flow better.

Studytime

iTrader: (15)

So jetblast, what are you saying makes them better? A better port? Exactly what is better?

Ben T.

GuitsBoy

iTrader: (4)

Semi Permanent Mold process as opposed to sand cast. Same thing with the 853 vs. 241 heads.

01Z0H6

iTrader: (63)

I read the same thing... I concurr...
Matter of fact,, i have a pair off of an 06GTO.. (243's LS2)

Studytime

iTrader: (15)

Cool. So, it only matters if you're not porting them. Thanks for the info.

Ben T.

Asmodeus

243's also have a 2cc smaller combustion chamber.