okay so ive been looking on here and havnt found to much info.

i would just like to know what or why the Gen IV 5.3 has so much more power than the Gen III.

 

It has the better flowing 799 (243) casting heads, and the TBSS style 90mm intake manifold/87mm t-body, Probably a little more cam as well, but not sure

 

thanks for the quick reply. ive just been wondering. my buddy has a gen IV while i have a gen III and i was just wondering why his had so much more power than mine.

i mean i realize its newer and has different parts. i just didnt know what all was different and was just wondering what all was different than mine.

 

Plus, I am sure all of the computer functions are a bit more updated(24x/58x)..But the main difference is the LS6 heads (799/243) and TBSS/GMT900 Intake

 

Newer ones have more compression too. All the little things add up to make a considerable difference.

 

as well as the better heads and intake/tb. i believe the gen iV engines have just a little more compression as well

 

Gen IV's all have flat top pistons in them like the Gen III L33's did..... which also had 243/799 heads but the regular intake manifold.

All Gen IV 5.3's now are 9.9:1 compression..... And laughably the 4.8 was dropped to only 8.8:1...

 

thanks everyone. that helps me alot.

 

Why is the 4.8 less than the 5.3 in compression ratio. Don't they have the same pistons/heads? My 07.5 4.8 has the same 243 heads as my brother's 2010 5.3 and if the pistons are all flat tops then why the difference? I'm confused.

 

Same piston and head with less cubes makes for less compression. Cylinder volume:volume at tdc. Lr4 was 9.4:1 with flat tops and smaller chambers. New ones are 9.1:1 I believe.