Rundeep66

I just got my stock bottom 6.0 running. Just wondering what to expect for mpg. Its a Carb 6.0 here is what I got

750 double Pumper, 620 cam, 240 duration 108 c/l, fully ported 317 not milled, gm single plane intake, 350 trans 4000 convertor, 410 gears with a 12 bolt, my truck should be around 3300 lbs. I got headers, flowmaster mufflers.
I was hoping for 14 to16 mpg

Paul57

I am not an MPG expert but I don't think you will get that (14-16) with 4.10s and that cam...not at 60+ mph, anyway. If you had an overdrive tranny such as the 200-4R that would help. I know of a builder that has them rated up to 1000hp if you're worried about strength.

kdavis

iTrader: (14)

a 2wd 2500hd only gets like 16 highway and they have 4.11 gears

dimetweaker

iTrader: (1)

and they have an automatic overdrive transmission to aid that as well... not looking good!

Rundeep66

Well I'll be finding out in a week or so. The 2500 hd has a lot of rotating mass it has to move. 50 lbs a wheel, a few extra pounds like maybe a thousand or more.

spacemanspif

iTrader: (5)

Don't forget that driving style is a HUGE factor in the gas mileage game.

LS1GMCTruck

iTrader: (2)

And they have the much better gas mileage, computer controlled fuel injection...also not looking good.

NemeSS

iTrader: (127)

its subjective,
too many ppl assume carb= bad mpg
but really its how well the carb is tuned for the motor its on top of and if the cfm rating, jetting, etc. is correct.

Paul57

I agree.
A carb should get the same fuel economy as fuel injection if the air/fuel ratio's are the same.

mred

iTrader: (5)

10-12mpg w/4.10s
4.10 eeek might kick yo ***.
might want to run some 3.42s or 3.55s 14-16 and drive it right.
i had close to the same set up and even ran a 28" tall tire all the time
650dp holley
but keep us posted.....

LS1GMCTruck

iTrader: (2)

28" tires, 3.42 Eaton Posi 10 bolt, LS1 4L60E, 27 mpg hwy.

mred

iTrader: (5)

Isolde

iTrader: (4)

That works out to 1800 rpm at 65 mph. I had a '78 Camaro, carb'd 350 with 700R-4, 3.08:1 and 26" tires, it did 26 mpg at 65 mph, which also was 1800 rpm. I strongly suggest 1800 at 65 if you care about mileage.

deelong4002

iTrader: (8)

I would think it's possible to get 14 to 16 easily if you have it tuned spot on. If not, who knows then.

726.0chevelle

iTrader: (17)

i think barely touching double digits if it ever sees them

52 Rat

iTrader: (4)

My '05 HD 2500 has the 410's with the LQ4. 13-14 mpg is it for me. Good luck.

Paul57

I believe that has a 31" tire also, correct???

Rundeep66

Well my truck is not doing the best for mpg. I just can't keep it under 3500. It's a blast to drive. I think I need a new Carb I'm getting a backfire and the truck will cutoff. But it will start right up besides that it's super fun. The weather in Chicago sucks

63chevyll

iTrader: (2)

When I had my stock carbed 6.0 w/small cam (206 210 duration) in my 63 chevyll w/4.30, th350, and 28" tires. I got 11 mpg without carb tuning.
I think 12-14 can be done with a carb.
derrick

Rundeep66

I'm looking to buy another Carb. I'm going to start back driving it after the first