If your 1980 has an original exhaust manifold as mine does - the O2 sensor screws into the manifold pointing almost directly back to the firewall. You should have no trouble using any wrench or socket. Personally I would use a boxed end wrench to crack it loose so you can keep your hands away from sharp objects on the firewall. Single wire O2 sensors are cheap so there no reason not to use Bosch. I've never torqued one -- make it reasonably tight. -- Dave

In my experience the slotted O2 sensor sockets aren't very useful. The one I had flexed and spread open when trying to remove the old. Ended up using an end wrench of remove the old (and subsequently install the new). That was on my Mini though. I don't recall ever replacing one on a 240.

The across-flats dimension limits of a 7/8" socket is only 0.0085"-0.0082" larger than a 22mm so using the "inch" equivalent shouldn't be issue.

Your 1980 will have only one sensor, probably just a single wire, cheap as they come.