[changzuki]

Lugging the replacement transmission into the "cave" to get a better look at it is the next step.
.

.
.
The story I was given is the transmission "is" a good working unit and the only issues with it have only been related to the electrical side of the overdrive engagement. It certainly "looks" decent on the outside.
.
The oil was drained prior to shipping so unless there was any residual inside, there wouldn't be much to go on. The two covers over the four-speed looked like standard bolt-on pieces. Their removal is pretty straightforward:
.
Fist the small cover. This gives access to release the shift rail and then the larger cover can come off:
.

.

.
.
Now the larger cover:
.

.

.
.
A closer look does show some wear on the first gear synchro. The original 1966 transmission was a non-sychro in first gear, and I learned decades ago how double clutch and/or use second gear's synchro, so this was not an issue.
.
There is an oil pickup screen on the bottom side of the overdrive unit. This linked photo shows it very well:
.

.
.
A little dirty but not bad. The tray magnet is also a little "silty" but not bad..
.
At this point, I'm thinking maybe any other issues will be minimal... that is until I tried to mount my 1966 bellhousing to the 1980 four-speed....
.
Oh, no, here we go again!
.
~CrazyJerry