Edelbrock RPM Performer package

A little more info needed- you speak of a "kickdown cable", factory used a mechanical linkage. Cables are aftermarket- whose cable/kit did you use? Factory or aftermarket throttle cable?
The following is for factory linkages:
Edelbrock Throttle Lever Adapter (manciniracing.com)
Carburetor Linkage Stud (manciniracing.com)
Carburetor Linkage Stud Nut (manciniracing.com)
Throttle Return Springs (manciniracing.com)
Restoration Throttle Return Spring Bracket (manciniracing.com)