tach reads 2850 at 65mph

[Albertan]

I thought I had a 3:73 due to the high RPM. I wanted to change the gears to 3:07 so the truck would run down the road at 65 with about 2200rpm. When we took the axle apart to rebuild it, I found the pinion had 14 teeth and the crown had 43 teeth. (14 into 43 = 3.07)

The guestion I have is that something does not make sense to me. Using some of the gear ratio calulaters on the net I should be running at 2200 RPM. I have p235R75-15 tires. The truck has a 402, turbo 350 tranny and running down the road at 65 the tach reads about 2850.