do any of you guys know what kind of gas mileage my truck should get. it has a stock 460 out of a lincoln. have a granny 4 spd. it has 3:50 gear in the rear

 

my 429 (close enough) in a 3\4 ton truck with an auto, 3.55's, and 33 inch tires has gotten up to 12 mpg on easy highway cruising. however, if i drive it hard constantly in mostly stop and go driving it can drop all the way to 5 or so. i would say an average would be 9-10.

 

With those gears, you should probably get around 11-12 on the freeway, depending on tire size and how "granny" your trans. is.
Im getting up to 14 on the freeway, with 3.00:1 rearend and 26" tires.
Good luck!

J/.c

1965 Ford Galaxie 500 (okay, so not quite a truck)
460/C6 transplant @ 389hp/491 lb.ft.
14.29@103.8, 13-14 mpg heheheheheh

 

2.75 rear, c6 tranny, 466 ci, 224/234 .572/.580 cam, stealth intake, 880 holley...gets 10mpg, loaded (5000lbs) or unloaded, doesnt make a difference. drive like my brother does and it'll get 2 gallons per mile!!