If the 243 and 799 heads are the same castings why is the 799 on the newer 5.3 trucks?
Any info on the 799s valve sizes and ?????
Last edited by 1 newbe; 12-21-2008 at 04:45 PM.
The 799's are the same castings but do not have the sodium filled valves the 243's have. The valve sizes should still be a 2.00/1.56. The all aluminum 5.3 HO (L33) started the trend with 799 and flat top pistons for a higher compression(9.9:1) than the old iron LM7. I believe all three 5.3L (LMG, LH6, LC9) have the same configuration now. One iron and two aluminum blocks.