2wd short wheelbase mpg

[76chevyc10]

I have a 1976 chevy short wheelbase stepside pickup that is all fiberglass except the cab. The truck is very light, It currently has a 350ci gas engine with a 700r4 transmission and a 2:77 rear end gear ratio. I'm thinking about replacing the engine with a 6.2 diesel engine non-turbo, any idea how many mpg it will get?

[Robyn]

A stock 6.2 in good shape should get in the high 20's if driven with care.

[john8662]

I saw as high as 25 with my '82. The 2.77 rear ratio won't score you milege though. Mine has (I think 3.08), a 2.77 will be a gutless turd.

J

[joed]

My 82 generally gives 21-23 mpg, mostly highway at 70-75 mph. It has a 700R4 auto and 3.08 gears.

Joe.

[Craig M]

A 2.77 and 700R4 will give you a great top end, 120 mph anyone? My much heavier Suburban with 700R4 and 3.73 gets 22 mpg with freeway driving at 65 mph or so. Wind resistance above 55 negatively affects fuel mileage quite a bit. Maximum milege is obtained if one can stay at 55 or 60 mph.