Need better fuel mileage

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Nate Dearth

Junior Member
Joined
Jul 5, 2017
Posts
1
Reaction score
0
Location
Athens Ohio
First Name
Nate
Truck Year
85
Truck Model
K30
Engine Size
377
85 k30 with smallblock 400 destroyed to a 377 and 4.10 gears with 8 inch lift on 38 inch pitbulls. Currently gets 9 to 10 mpg but I need to get better than that. Was wondering how much of an impact changing to 3.73 gears and maybe going a little smaller of a tire would do. Maybe 35s. Any suggestions?
 

Honky Kong jr

Super Sarcastic Man
Joined
Jun 14, 2016
Posts
14,968
Reaction score
9,789
Location
Denver,PA
First Name
J-me
Truck Year
87
Truck Model
V10
Engine Size
Lil BB 407
85 k30 with smallblock 400 destroyed to a 377 and 4.10 gears with 8 inch lift on 38 inch pitbulls. Currently gets 9 to 10 mpg but I need to get better than that. Was wondering how much of an impact changing to 3.73 gears and maybe going a little smaller of a tire would do. Maybe 35s. Any suggestions?
That will cause you to use the go pedal a bit more to get that heavy som bitch moving. With all your fuel mileage killing variables 9-10 ain't bad. Other then a cost of going to a 4L80 and fuel injection that is or even a 6L80.
 

smoothandlow84

I'd rather be draggin' frame
Joined
Jan 4, 2015
Posts
2,121
Reaction score
784
Location
Arizona
First Name
Steve
Truck Year
1984 Frame...87 motor and 700r trans
Truck Model
1500 r10 pavement scraper
Engine Size
350 TBI
Great fuel mileage and squares.....not common. 9-10mpg with your setup sounds about right
 

theblindchicken

Full Access Member
Joined
Oct 24, 2013
Posts
1,518
Reaction score
265
Location
SoCal
First Name
Christian
Truck Year
1974
Truck Model
K10 5" lift + 2" BL
Engine Size
350-4, 0.030" over
I'd be happy with 9-10 consistent.

With 4.10's, th350, np203, and 35's under a 4-5" lift was only giving me maybe 8 mpg. But could be the difference in the drivetrain and the tune of the engine as well.
 

Affende

Full Access Member
Joined
Apr 14, 2014
Posts
155
Reaction score
47
Location
ColoRADo
First Name
Affende
Truck Year
83 and 84
Truck Model
C1500 and K3500 3+3
Engine Size
250 and 454
my 84 3+3 454 + sm465+ 208 .... 7MPG with the welder and gear in the truck .... downhill .... with a tail wind.

ill be moving to MPI next year.
 

theblindchicken

Full Access Member
Joined
Oct 24, 2013
Posts
1,518
Reaction score
265
Location
SoCal
First Name
Christian
Truck Year
1974
Truck Model
K10 5" lift + 2" BL
Engine Size
350-4, 0.030" over
my 84 3+3 454 + sm465+ 208 .... 7MPG with the welder and gear in the truck .... downhill .... with a tail wind.

ill be moving to MPI next year.

Engine off and trans in neutral too? Just bump start her every time you hit the bottom of the hill.
 

74 Shortbed

Full Access Member
Joined
Aug 12, 2013
Posts
6,306
Reaction score
1,411
Location
*
First Name
*
Truck Year
*
Truck Model
*
Engine Size
*
My 73 dually with a big block got 8mpg uphill or downhill towing or empty when I got it, a little tuning and a GearVendors overdrive running empty at 78-80mph under "ideal weather conditions" I managed almost 15mpg, towing the boat with fuel and tools and crap I got 14mpg, with a 11 1/2" self contained camper on it I got 9mpg..

You must be registered for see images attach
 

Honky Kong jr

Super Sarcastic Man
Joined
Jun 14, 2016
Posts
14,968
Reaction score
9,789
Location
Denver,PA
First Name
J-me
Truck Year
87
Truck Model
V10
Engine Size
Lil BB 407
My 73 dually with a big block got 8mpg uphill or downhill towing or empty when I got it, a little tuning and a GearVendors overdrive running empty at 78-80mph under "ideal weather conditions" I managed almost 15mpg, towing the boat with fuel and tools and crap I got 14mpg, with a 11 1/2" self contained camper on it I got 9mpg..

You must be registered for see images attach
Well lay tee dah lol :rotflmao:my pos 2015 f250 extended cab utility body with a 6.2 6spd auto gets 11.9mpg. Lol so op should be happy as a pig in **** with what he is getting.
 

74 Shortbed

Full Access Member
Joined
Aug 12, 2013
Posts
6,306
Reaction score
1,411
Location
*
First Name
*
Truck Year
*
Truck Model
*
Engine Size
*
Well lay tee dah lol :rotflmao:my pos 2015 f250 extended cab utility body with a 6.2 6spd auto gets 11.9mpg. Lol so op should be happy as a pig in **** with what he is getting.
:happy175::happy175::rotflmao::rotflmao::laughing1::laughing1:
 

theblindchicken

Full Access Member
Joined
Oct 24, 2013
Posts
1,518
Reaction score
265
Location
SoCal
First Name
Christian
Truck Year
1974
Truck Model
K10 5" lift + 2" BL
Engine Size
350-4, 0.030" over
Well lay tee dah lol :rotflmao:my pos 2015 f250 extended cab utility body with a 6.2 6spd auto gets 11.9mpg. Lol so op should be happy as a pig in **** with what he is getting.

If you stopped towing the ford around, you might actually get some decent mileage for once!!!! :crazy::happy175:
 

Honky Kong jr

Super Sarcastic Man
Joined
Jun 14, 2016
Posts
14,968
Reaction score
9,789
Location
Denver,PA
First Name
J-me
Truck Year
87
Truck Model
V10
Engine Size
Lil BB 407
If you stopped towing the ford around, you might actually get some decent mileage for once!!!! :crazy::happy175:
Lol it ain't my fuel card I just keep filling it up. It's funny I'm die hard Chevy but across my driveway sits 2 Edges an explorer and an f250. My truck is in the garage and there is a 97 oil leaker lumina with less then 30k on it sitting here too.
 

75Monza

Full Access Member
Joined
May 5, 2017
Posts
1,362
Reaction score
2,840
Location
Colville, Washington
First Name
Jeremy
Truck Year
1980, 1982, 1985
Truck Model
K30, K20, K20
Engine Size
454, 383, 350
I got spoiled with the mileage my 99 cummins got, it was a 3/4 ton long bed quad cab slightly tweeked 24v, on the highway I got 22, towing got 14. Often ponder putting a 12v in my square after remembering why it came with dual tanks, lol...only briefly until I picture how heavy that would make the front of my truck. The Square is my favorite truck style, so I just totally ignore how much fuel I put in it and try to offset that amount driving my toy Metro around at 52mpg.
 

rt66paul

Full Access Member
Joined
Apr 16, 2016
Posts
230
Reaction score
109
Location
California
First Name
paul
Truck Year
1991 suburban
Truck Model
2500
Engine Size
7.4
yeppers. Just be glad it is not a big block Suburban. If I lifted it for monster tires with a big roof rack on Calif gas, I would get maybe 4 mpg..............
 

roadracerga

Junior Member
Joined
Mar 6, 2017
Posts
14
Reaction score
3
Location
ga
First Name
charles
Truck Year
1980
Truck Model
c30
Engine Size
350
85 k30 with smallblock 400 destroyed to a 377 and 4.10 gears with 8 inch lift on 38 inch pitbulls. Currently gets 9 to 10 mpg but I need to get better than that. Was wondering how much of an impact changing to 3.73 gears and maybe going a little smaller of a tire would do. Maybe 35s. Any suggestions?
 

roadracerga

Junior Member
Joined
Mar 6, 2017
Posts
14
Reaction score
3
Location
ga
First Name
charles
Truck Year
1980
Truck Model
c30
Engine Size
350
Big tires are a killer dropping down tire size will also decrease the rolling wait that will help with your mileage anything bigger than 33 just gonna hurt you 38 you're just tough to get better than 10
 

Forum statistics

Threads
42,116
Posts
909,464
Members
33,611
Latest member
RNFL
Top