The speedometer gearing is set up for the 849 revs/mile of the OE 185/65R-15 tires and the axle ratio is 3.27:1, so revs at 60 are 849 x 3.27 = 2776.

Tires with a different revs/mile spec will not effect this relationship, but they will impact speedometer accuracy, and as previously stated, the auto trans starts in second gear unless you floor the throttle. Fourth (top) gear is direct and there is no "overdrive".

Duke