I am thinking about picking up a extended cab 4.8... got a 02 5.3 right now but what is the horsepower gain difference between the two... can you get pretty close to the same power as the 5.3

 

My brothers truck,05 ecsb z71 4.8, 87 black bear tune, 4.56s, 315s, corvette servo will walk my dads 06 CC z71 with 5.3, 87 black bear tune, 3.73s, 285s, corvette servo

 

the 4.8 will make about the same amount of power as an equally built but around 500 RPM or so higher...they're more doggy down low so gearing is more critical with the smaller motor but they can definitely run so long as you don't mind revving them up a little higher. is that an extended cab long bed or short bed? the extra weight of the long bed chassis will not mix well with the 4.8...what are your goals for the truck?

 

weight and lower gearing is what made you brothers truck walks over your dads truck

if the 5.3 had 4.30s or 4.56 itll walk over the 4.8

 

If it was a 2007+ truck then the 4.8L isn't bad at all. The 2007+ engines have more power than the older year engines btw.

If I did have a choice though I would rather have the 5.3L.

The 2002 5.3L has 285hp iirc and the 4.8L in the same year would be 270hp. If you want to find out the tq ratings google it. A 2007+ 4.8L would probably be pretty close in power as a 2002 5.3L.


*EDIT* Here is some reading info on wikipedia.. http://en.wikipedia.org/wiki/GM_Vortec_engine

 

5.3 is generally +30hp/+30tq over a equal year 4.8

Id say an 07+ 4.8 vs a pre 05' 5.3, the 4.8 would be equal/faster up top.

 

I thought today the newer trucks 5.3 had 315 hp and the 4.8 had 295 at the fly wheel that is and torque was about only 10-15 difference I could be wrong though

 

I thought the 5.3 made it up to 325.

Either way, from dynos Ive seen, a cammed, bolt on 4.8 usually makes 280-300rwhp, cammed bolt on 5.3s put down 320-330.

 

I made 305whp on a nitrous tune with just headers NA

 

then the 4.8 need 5.13's or 5.38's

yeah the 4.8 too small for a heavy truck