I'm new to this forum kinda stuff and couldn't find nor figure out what I wanna to know. I got a 1992 f150 custom with a 5.0 3 speed auto both with 269xxx miles on original motor and tranny with manual front lock in hubs, not sure about gearing. I'm wanting to put either a 4-6" lift kit and either run the 33x12.5r15 or 35x12.5r15. I seem to get pretty crappy gas millage as it is taking a guess maybe 10 mpg right now. If I lift it I'd like to know how much it will drop to help decide on what size. The truck will be driven mostly on the black top due to the fact she don't have any rust on it right now but family members driveways and everything is red clay bud and such. Estimated gas millage help please

 

If you are getting 10 now, it will probably drop to 8.

I didn't think they still had the 3 speed in 92, you sure you don't have an AOD or E4OD?

 

Not entirely sure. I know the my dash has 1,2,d or overdrive. So I'd say it would be a 3 speed auto.

 

Nope, that's a 4 speed overdrive transmission.

If the quadrant says P R N (D) D 1 it's an AOD.
If the quadrant says P R N (D) 2 1 it's an E4OD and it will have an overdrive lockout switch either on the end of the shift **** or on the dash.

If you are driving it with overdrive locked out you will get terrible gas mileage.

 

I got the e4od transmission then and I always have overdrive activated.