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

Thanks, Cudamark . . . it is a 4 speed, I am willing to sacrifice mileage for some mini-muscle feel. 8)