Rear End Ratio question

I have a Magnum crate 360 mated with a TorqueFlite 727 transmission. The rear end is a Dana 60 from Strang Engineering with a 3:54 to 1 ratio. In 3rd gear when the car is doing 60 mph the engine is turning at 3,000 rpm. This seem way to high of rpm to me.

Do I need a taller rear end gear?

Can I change the shift points in the trans?

Thanks for the advice.