Also suspect the temperature control valve. Mine broke, leaking coolant all over the floor. The early model has a funny valve mounted on the fire wall, they are expensive and a pain to replace. Not sure about the late model, it might have the same setup as in the 240 which is made of plastic and prone to crack.

Expensive for the kickdown cable, try www.scandcar.com for a replacement. I'm in New Zealand, and Scandcar is the only source for me. Your kickdown cable is about US$75 plus shipping. Not sure about your 164 setup, my '71 144 with twin Strombergs also has a plastic bushing in the firewall that wears out (it is for the metal rod which drives the accelerator linkages to the carbs, which also has the kickdown cable connected to it). Scandcar supplied me with a replacement bushing, they are great for those kind of hard to find items.