Originally Posted by
CSaddict
The chart it comes with says its in the 7.2ish. It would need a huge pinion to get to the 4 range.
I use a 82 spur and 47 pinion to get a 4.25fdr for 17.5. I can probably still gear up to a 48 or 49 pinion since I temp around 140F. The free drive train is helping with the temps so keeping it smooth is one area to take care on.
BTW, anyone know where I can get a 64P 48-50 tooth pinion? All of the places that I shop are missing the entire line from 46-50 for some reason.