I have a 1990 F-150 L-6 4x2 with the e4od transmission. I wanted to know what ring and pinion I should upgrade to I currently have a 3.08 I get around 13mpg. If I changed out the ring and pinion what would my rpm be at 65? I will be running 28" to 30" tires. During the summer I pull a trailer often around town cutting grass. Any advice is appreciated. Thanks.

 

This is a good little program for figuring tire / gear related conversions .

http://www.4lo.com/4LoCalc.htm