What rear gear ratio is good for highway???

[capev86]

if you want to use your truck on the highway but still want to be able to accellerate, pull loads, etc, there are two words to consider....OVER & DRIVE

i would not want anything less than a 3.42, even in a 1/2 ton. the 3.08 makes for lousy get up and go. a 3.73 with a .7 overdrive comes out to 2.61.....way better than a straight 3.08 in top gear. 3.73 gear isn't bad when you are towing and staying under 60mph. gas mileage is best if you keep the speed low too, regardless of the gear ratio....trucks displace a lot of air and those forces add up when you get moving at modern highway speeds.

my 72 burb 3/4 ton has the 4.57 geared ho52 and i have a 4.10 3rd member to go in with plans to install the factory OD tail shaft on the original 3 speed saginaw (3OT). that will equate to a 2.89 final drive when overdrive is engaged. right now i figure the 307 turns about 3100rpm at 60mph, so i keep it under 50 for long drives and only go higher for short jaunts.