I bought my 442 as my primary driver, so having most of the comforts & features of a more recent car is important to me. That's why I looked long and hard for one with a functioning air conditioning system and with power windows.
The two features my car lacked at purchase that I most missed were cruise control and wiper delay. I have now finished installing the former, and will give you the details here.
I bought the unit from J.C. Whitney (see ad below) on sale for $69.99. I followed their instructions and ordered the magnet kit, but it turned out that one was included with the unit, so don't make that same mistake.
The installation went well, with one e-mail (they immediately responded that I should call their support number - 1-800-225-6074) and one phone call (they answered my question promptly and accurately - they were only contacted because I had misplaced the original magnet sensor and the connectors with the normally-unnecessary magnet kit were different).

(You lucky folks with manual transmissions get to skip this step. The unit will just count pulses from the tach connection on the coil.)
I found that one of the floor pan reinforcements made an ideal spot to mount the sensor. I ground down one edge (see photo #1) so that it would fit a bit more tightly under the car. I'll shorten the bar and add one more screw to finish it off.
Photo #1This is tucked away pretty safely from road debris and exhaust heat.
This will vary with your carb, but picture #2 should give you an idea. I would prefer to have a bracket anchor the carb end of the cable, but nothing worked out easily for mounting the bracket, so I used the clamp. It works fine.
Picture #2
Well, this is described reasonably well in the manual. I found a good-sized opening in the firewall just behind the left cylinder head.
This is a temporary set up while I tested the unit. I will probably end up mounting the vacuum unit inside the left front fender, near the battery. It's much easier to route wiring neatly from there, plus it's further away from engine heat. I'll have to drill a hole or two, though! (see picture #2 for the vacuum line connection)
I didn't want to drill any holes I didn't have to, so I have started with mounting the control unit under the dash, near my auxilliary gauges. I fashioned a mounting bracket out of an old license plate, hammering it flat, bending it into a "L" shape, and then using a "nibbler" to notch out a slot for the wires on the back of the control unit to pass through. This makes for a bit of a stretch for my 32" arms, but isn't bad and requires no drilling. Let me know if you come up with a better solution.
Picture #4
Picture #5This thick bundle of wires is the primary reason I didn't mount the unit on the dash.
Picture #6It's pretty inconspicuous down there, yet fairly reachable. No problems with my right leg hitting it. So far I've tested it from 35 to 65 mph with good results. (If anyone knows of a good way to keep your keys from scratching the dash, let me know!)