More HP on 273 Stock 63 Dart GT Vert?

If yours is a 4 speed, you won't need kickdown linkage. A 3.23 or a 3.55 will work fine for your application. 3.23 will give you a little better mileage and lower RPM's for freeway use. 3.55 will get you more acceleration and higher RPM's but less mileage. your choice.....
Mark

Yeah, it is a 4 speed . . . drove it yesterday . . . got some synchro issue to take care of, but what a load of fun!!!!