Whats the story with the 799 heads? I have read thread after thread and I am confused. Are they for a 5.3 bore or a 6.0 bore? Are there any benefits of running them on a 6.0 over the 317s?

 

the 799s and 243s are the same just different numbers?

they come on the newer 4.8/5.3s and they came on the LS6s. (i think) but they only difference in the 799/243 and 317s is the Chamber.. the 317 is a 72cc and the 799/243 is a 66 or 68cc.. cant remember.

 

that would explain why my old 07 5.3 made so much power with just bolt ons

 

317's heads are off 6.0 , but ther are interchangable with any lsx motor.. meaning u can run them with a 5.3/

317's and 243's have the same flowing , but different CC
317's are mostly used for boosted applications..

read post #4 , a little info on heads..
https://www.performancetrucks.net/fo...&highlight=862

 

799's and 243s are the same, other then the casting, and what year engines they came on, both of the smaller motors. 4 inch bore<