lifted diesel help

[bigchevyc30]

can anyone help me im looking at a 83 k-30 with a 6 inch lift on about 34 inch tires with 3.73 gears and a turbo 400 tranny. im wanting to know if anyone could tell me about what the mpg would be. heres what it looks like its not that great as its a pic i got with my phone

[bake74]

     A well tuned 2wd diesel driving normal should get anywhere from 23 - 26 or so MPG.  So a 4wd (since more moving parts ) In the same situation, I would assume anywhere from 20 - 24 MPG.

[Edahall]

1983 was a good year for fuel mileage if that's what you're after.  The newer the 6.2, the more fuel they used and the more power due to larger precombustion chambers.  With that truck, you'll lose some fuel economy due to the 400 transmission and the lift.

[4x4x4x]

can anyone help me im looking at a 83 k-30 with a 6 inch lift on about 34 inch tires with 3.73 gears and a turbo 400 tranny. im wanting to know if anyone could tell me about what the mpg would be. heres what it looks like its not that great as its a pic i got with my phone

if the 6.2 is running properly you should expect anywhere from 16 to 20+ mpg. the 34" tires will cause the transmission to drive like it is in od in each gear.  the engine could lug some while starting from a stop.  with less aggressive tires you could gain up to 2mpg. syntethic oils and lub wll also help to increase mpg.

our 85k10 with a turbo 6.5, 700r4, and 33/1250/15's goodyear mtr's gets upto 22+mpg hwy.

[Edahall]

if the 6.2 is running properly you should expect anywhere from 16 to 20+ mpg. the 34" tires will cause the transmission to drive like it is in od in each gear.  the engine could lug some while starting from a stop.  with less aggressive tires you could gain up to 2mpg. syntethic oils and lub wll also help to increase mpg.

our 85k10 with a turbo 6.5, 700r4, and 33/1250/15's goodyear mtr's gets upto 22+mpg hwy.

Yup, the 16-20 mpg is probably a realistic figure for this truck.  From the pictures, it appears to also have non lock out hubs.

With lift and large tires, you really get penalized with speeds especially over 60 mph.

One thing that would really help on this truck for fuel economy would be to get a tighter / slower stall  torque converter.  It would get rid of a lot of that slippage and transfer more power to the ground.  Diesels have a lot more low rpm torque so a slippery torque converter doesn't give it nearly as much benefit as on a gas motor. 

[cbr600rr]

I'm getting 16-17 in mine thru town/ light highway and thats with 38.5's