1965 Dodge Dart high RPM issue

[65 Dartman]

You may want to check that the correct speedometer gear is installed for your tire size and axel ratio. 20 bucks for the right gear, if needed is a lot cheaper than a speeding ticket.

Good point on checking for the right speedometer pinion gear. This chart is for the 904 transmission with 13 inch tires according to my 65 FSM:

Tire 2.93:1 3.23:1 3.55:1 3.91:1
Size

6.50-13 17-orange 19-Dk Blue 20-Green 21-Gray
6.70-13 16-Brown 17-Orange 19-Dk Blue 21-Gray
7.00-13 17-Orange 18-Dk Purple 21-Gray 21-Gray

These speedometer pinion gears are not being reproduced available only used. I think the $20 as referenced is for the later, common pinion gears.