Electrac Locker 4.56 gears and 35 spline axles
I have an 01 7.3l E350 Quigley van with 33" tires (285/75/16). It came with 3.55 gears and open differentials. The gears were just too tall for the tires and the motor simply did not like overdrive. Those of you with similar ford transmissions might know that we have extra high overdrives that are .71:1. I used grimmjeeper.com to calculate what ratio would be close, or just a little lower than a rig with 4.10's and stock tires. Since my van actually liked to run down the highway in drive with the 3.55's, I decided 4.56's would be perfect. They would put me right at 2300rpm going 70mph. I also found Electrac lockers front and rear for $400 a piece thanks to Randy's Ring a Pinion (sorry, I think I got the last ones). I wanted the experience of gear setup, so I decided to purchase a diff spreader and setup bearings, which I would definitely recommend to anyone considering tackling this job. This being my first ring and pinion setup (I had expert help from a friend), it took quite a while, but well worth the time and money spent. Plus, I know they were done right. As most of you may know, our stock full float Dana 60's are 32 spline and diff choices are limited. But, $300 can get you cut to fit 35 spline axles which allow you put in pretty much anything you want. No spindle boring is necessary, they fit right in. I couldn't be happier with my choices and anyone that has questions is more than welcome to ask.
Dreaming since 2000