I would try a 39 tooth, your a bit high on the 40 tooth, bet your right in there with a 39 tooth. I run a 3.91 with a 28.5 drag radial and a 35 tooth gear I'm within 1 mph
I decided to go with a 38 tooth gear, hooked up the GPS and took it for a ride. I'm no longer 5 mph fast on the speedometer, now I'm 10 mph fast. WTF gives ?
