On the handling front, you might consider changing any tired, cracked bushings, ball joints, tie rod ends etc. I did this front and rear and then installed IPD anti swaybars(front and rear) and Bilstein heavy duty shocks (front). The rear got Boge shocks. The ride is much improved. I would have installed Bilstein shocks in the rear too but it is unclear to me whether the the shock for the 240 can be used on a 72 140/160. I cannot find a Bilstein shock listed for the rear of early 140/160 cars.

On the electrical front, I added electric window winders (rear only because the car has the front vent window), electric door control with remote, front seat heaters, intermittent window wiper function, and a bunch of gauges.

For the electric windows, I used winder units from a 240 and switches from 240 and 740. There is a little catch all bin between the front seats for which I fabricated a plastic top cover with cutouts to hold the control switches. To run wires from the B pillar to the door, I used rubber accordian parts from 240 and cut elongated holes to fit. Volvo did not offer electric window winders until the introduction of one piece front glass and the entire geometry of these is different from the earlier vent/window setup.

For the electric door controls, the solenoid units were taken from 240, the relay and control switch which reverses polarity come from 740 and I used a window control switch, but wired differently, as a manual inside the car lock/unlock. It too is mounted in the center console mentioned above. Here's how it works: A remote door controller which I got from JC Whitney is wired to the control relay, which is in turn wired to a door solenoid mounted in the drivers side front door. This solenoid is activated by either turning the key or pressing the remote lock/unlock button. This in turn pushes or pulls the door mounted polarity reversing control which then activates the other door solenoids. To run wires to the doors, I used rubber bushings from 740 and drilled holes in the front door edge and body. Note that the holes should not be opposite each other, but rather offset to minimize wire flex each time the door is opened or closed.

The front seat heaters were installed along with new seat upholstery and are wired through individual relays and on/off control switches mounted in the center console. (Probably the least interesting of the changes).

Intermittent wiper function along with simultaneous wiper/washer function is a matter of wiring the relay on the low speed wiper setting between the control switch and the wiper motor and adding an on/off switch specifically for the intermittent function.

I followed the Volvo green book wiring diagrams from 740 as guidance and made a few mods(but not many).

I added an ammeter, vacuum gauge, oil pressure and temp gauges, an electric fuel pressure gauge and an air/fuel ratio gauge. On this front, the oil temp gauge sender is mounted in the oil pan drain plug. I had a machine shop tap a 1/8-27 pipe thread which holds the sender. The only drawback is that you must remove the sender wire before undoing the drain plug. For the oil pressure sender, I installed a "Tee" in the existing pressure sender hole so I could keep the idiot light and also have a gauge sender. (Now I have learned that there are senders which have contacts for both but incompatible with the gauge I already have.) The vacuum gauge hose is attached to a threaded nipple which sits in a hole tapped into the aluminum exhaust manifold. (Look for a nice thick boss on the manifold to do this and clean up metal shavings afterward). The electric fuel pressure sender is mounted off a tee in the fuel line near the cold start injector. The O2 sensor for the air/fuel ratio gauge is a cheapy generic mounted on a bracket with welded on nut in a hole I drilled in the exhaust pipe just below where it joins the exhaust manifold. All the gauges are mounted in a pod I fabricated which sits just forward of the gear shift lever or in the vertical center console which used to have an AC vent, a clock and a couple of other switches. I cut out the flat mounting surface , fabricated a replacement from thin rigid plastic sheet covered it with black naugahyde and glued it in place from the rear with a few scraps of plastic and silicone window caulk.