GWEE

My 16yr old son is about to start driving my 2010 1500 excab Chevy Z71 and we're talking about doing things to it. It has the. 5.3L LC9 engine with 6L80e trans and would like to mod the engine. Right now we talking about a 1.25" bodylift and 7.5" suspension, 22" rims wrapped in 35" toyo tires, 4:56 gears. As for the LC9 i was thinking hand porting plus bigger valves a set of 243 heads i have to replace the 799 heads. Get bigger injectors and throttle body and a retune.

My main question is what kind of cam would work with a 4 x4 that sees mostly highway miles and some off roading. Hope I didn't leave anything out.

Jason Z69

I would keep the 799 heads. They flow just as good as 243s. Or thats what I was told. I have the 799s on my 2010 5.3.

black00chev

iTrader: (2)

Whatever you do, unless you want it to be a dog out of the hole I wouldn't mess with the heads and valve sizes too much. You will want as much torque down low that you can get with the lift/tires/gears. In fact, it would almost even be better off to leave the engine stock, and maybe consider a blower (with bigger injectors).

Atomic

iTrader: (42)

Dont bother with the heads, you need gears and a roots blower.

GWEE

Thanks for the advise guys

FFDP

iTrader: (2)

Do expect fuel mileage to tank once you lift it and put massive rims and tires that are really heavy and the gears.

GREENSIERRA

gears and blower would defanitly make it a lot more fun to drive

LOBO2

iTrader: (4)

799 & 243 heads are the same, just different casting numbers.

This is what I found on a corvette forum,

"There is no difference between the two heads. The numbers tell what original mold the casting came from. 243 mold was done at GM Research, the 799 mold is used by other vendors. The same vendor will have 243 and 799 molds. The numbers are just a GM system for when the mold was made. If a head had a problem it helps them track down where the problem started. The only difference between the heads is production variance."