change of gearbox żdo it or not?

[GUILLERMOARIAST]

Hi people, i have a 1980 Blazer 4x4 with manual gearbox the principal and the low one, it has 31" x 10.5" tires. It gives to me 17mpg and that is too little. I use the truck only for traveling, because for daily drive i have a compact car.

Thus, my mechanic suggested me to change the principal gearbox taking one from a Dodge D500 truck with five speeds, i believe this is a Clark 2622 gearbox.

I think this change will give to my Blazer more final velocity contributing to save fuel on long trips.

What do you think?

[VeeTwin60]

I wish I could get even close to 17mpg 

[Redneckchevy]

I dont even see close to 17mpg with my V6 lol

[78BBSTEPSIDE]

What does 17 MPG feel like!!!!!!!!

[Captkaos]

If you want a 5 speed get a NV4500 for a GM.