I am driving with one and its great . Went from Louisiana to North Carlonia and back a couple years ago with it.
I bought the 3.91 off ebay. Then I took it to my buddy Skip in Arkansas. You know Budweiser its not just for breakfast guy.
He had some guy convert it to 3.64 for, get this, $100
Skip had a old diff with 3.64 that they robbed the gears from. Hard to beat $100.