Alot of folks have done alot of different stuff with their trucks, ie; 4.8 to a 6.0, hogg out a 5.3 to 5.7, straight LS1 drop in, while many opt going right up to the 6.0. I'm after the last mod, the 6.0; as many folks that have done it, I'm kinda hesitant as owners of the HD trucks are less than enchanted with gas mileage. But swapping said 6.0 beast into a half ton truck, what were any effects on gas mileage.
Figured instead of going the trouble to punch out the 5.3 to 6.0 I can get a 6.0 iron block from Scoggin for around $600, and an aluminum one for another $300 after that...........

 

The HDs also have a 4L80 and weigh a little more than your truck.. and most of them have 3.73s and 4.10s... im goin to guess yours has 3.73 being a 4wd? or 3.42s..

It depends on alot of things...

 

Yeah- I have 3.73's. Was also wondering how much the 4L80 eats up, I'm planning to stick and FLT 4L6x behind it. Be kinda nice to have a little more punch up here at 7,000ft, any recommendations or comments on the Crane Gold rockers.................

 

your gas milage isn't going to really change that much. well other than you will want to floor it alot more.

 

That's what I'm thinkin', what with the weight of the truck remianing the same, but I still wonder why the 3/4 ton trucks suffer on mileage so bad, is it their extra weight, the 4L80 and I won't even mention 4.10 gears..........

 

also factor in that 2500hd trucks weight 7000+ pounds. That's about 1500 lbs. more than your truck. The problem with the 4l80e isn't so much the parsitic drivetrain loss but the o/d ratio(.75 I believe instead of .70) is going to make you turn more rpms at highway speeds.

 

Are you saying that because he is an AWD extended cab or just comparing engines.

I was under the impression that the 6.0L got about 12-14 in the city and 15-17 on the highway.

My RCSB with 3.73's gets about 15-16 in the city and 18-21 on the highway

 

Again, like I just said that's in a 7000 pound truck

 

It;s not AWD- I just stuck the C3 monniker on there. The truck is a 5.3 with manual/ stick part time 4wd. In the grand scheme of things, I have made it from here, Santa Fe NM, to Sayre OK on a tank of gas with a 400lb ATV in the back..........

 

I can pull 17 or so interstate MPG with my 6.0, but that's full time AWD, auto, 410's, and short 275/45/20's. When I had my 275/55/20's I could pull 19-20 interstate, and that was before any real mods other than a tune.