Mark Johnson

iTrader: (1)

I'm a little late to the party so I'm askin' y'all in the know. I know that the new 5.3's have the TBSS intake manifold but I also heard something about the heads. Are the new 5.3's packin' 243 heads off the LS6? That would rock...........
Thanks

LS1FREEK

iTrader: (1)

YEP! They're either packin those or the 799 heads. But they are both the same head. The only difference between the truck heads and the actual LS6 heads are the springs and they dont have the sodium filled valves, which the LS6's do.

Mark Johnson

iTrader: (1)

Thanks, Freek. One more Q; what with the 243's and all, doesn't that affect compression? And if so- would I be better off with some ported, TEA 5.3 heads........

LS1FREEK

iTrader: (1)

The new 5.3's also have flat top pistons... I think they are close to 10:1 compression now.. But yes, if you put the older 5.3 heads on you would gain some compression. About a half a point.

Mark Johnson

iTrader: (1)

Ahhh, flat top pistons; that's the difference. Well thank you very much..........

LS1FREEK

iTrader: (1)

No prob!

iamkeniff

iTrader: (16)

can you verify that the 5.3 is 10:1? i thought they were 9:5:1 considering the 6.0 is a 10:1 and the L92 is a 10:5:1 just curious bc ive never seen any type of info on a Gen IV 5.3 having that kind of compression

trever1t

iTrader: (14)

don't know about the Gen IV but the Gen III 5.3 L33 with flat top pistons and 799 heads is 9.9:1.

Preston129

iTrader: (3)

9.95:1 As stated in my service manual.

iamkeniff

iTrader: (16)

SWEET i always thought they had 9:5:1 but thats good that it has such a high compression.