I have an aftermarket cruise control on my truck. I bought it from
www.rostra.com. Hot Rodders use their systems. Mines an older model with vacuum control. Now, they have all eletronic systems. All you do is add an output signal generator between trans/cable or driveshaft. Based on input speed, the module adjust throttle. You would only have to add another cable to the carb. Below is a pic of connections. I like it. You have to be ready for use!! Mine will pull the throttle to the floor if I hit the accel button from a low speed. Great accel and use. Worth every penny in my book and highly recommended.