243 heads found on LH8/LH9 2009-2012 5.3L Colorado? On a 4.8L with a LS6 cam?
08-19-2012, 04:09 PM
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243 heads found on LH8/LH9 2009-2012 5.3L Colorado? On a 4.8L with a LS6 cam? I might be able to get a set of heads from a 5.3L 2012 Colorado, I think they are 243 castings same as LS6, but does not have the sodium filled light weight valves. Will I loose a bit of compression going to those heads on my 2007 LR4 4.8L? They will definitely flow better. As far as I know the late 2008 to 2012 4.8L and 5.3L come with the 243 heads, and use the same pistons and rods as the earlier year motors do, the newer ones make more power..is that were the gains are?
I'm thinking of swapping in a LS6 cam as well, will I need the yellow valve springs as well? And LS6 push rods? I can use my stock lifters though right?
I might pick up a set of LS2 injectors as well! My goal is 330-340 HP at the fly-wheel, and about 325 ft/lbs. I'm currently about 300+ HP and under 300 ft/lbs at the fly-wheel
I'm thinking of swapping in a LS6 cam as well, will I need the yellow valve springs as well? And LS6 push rods? I can use my stock lifters though right?
I might pick up a set of LS2 injectors as well! My goal is 330-340 HP at the fly-wheel, and about 325 ft/lbs. I'm currently about 300+ HP and under 300 ft/lbs at the fly-wheel
08-19-2012, 04:19 PM
#2
Earlier 5.3 motors have dished pistons and smaller combustion chambers in the heads...the later 5.3s have flat tops which is why they use the 243 heads with ls6 spec chambers....
So to answer if the 4.8 is an earlier motor you will lose some compression by swapping the heads but they will flow more..
So to answer if the 4.8 is an earlier motor you will lose some compression by swapping the heads but they will flow more..
