I installed an after market vacuum conrolled cruise in my 72 164 but its so long ago I dont remember where I purchased the kit. Nothing difficult about the installation except some wiggling around to thread wires from one place to another. The control unit has a vacuum bellows and the electronics inside as well as a short cable which attaches to the accelerator linkage. Other connections are to the (-) side of the coil, the stop light wire, a fused power source, the control module at the directional signal stalk and a tap to get vacuum. Thats what I remember. I think the most difficult aspect of the entire installation was locating a suitable place for the control unit so there would be a straight shot for the cable to the accelerator linkage and clearance for the engine lid to close. I chose the passenger side front fender on top of the channel shape which runs from the rear of the engine compartment over the wheel well.