What amp is the alternator?

View attachment 1715528664 View attachment 1715528666 No numbers by the BAT post. On the backside, about 90 degrees down, it looks like “069”, “960”, or GRD. Hard to tell. The ear in the front is marked with some sort of hieroglyphic. See photos
Yea. That case has been sandblasted.

Here's one you can read pretty clearly.
upload_2020-5-15_17-38-11.png

I think from looking at the back case of yours, that's a '70-'71 and probably has two insulated brushes.
You can use it with the earlier voltage regulator by grounding one of the brushes. If you want it to look 100% correct, at least to the extent we couldn't tell in a photograph, that's another story.

Arrow is pointing to the part of the casing I noticed is different.
upload_2020-5-15_17-48-25.png

upload_2020-5-15_17-51-2.png

Compare that with the '70-'71 version with both brushes insulated.
upload_2020-5-15_17-53-48.png


I'd say the only way to know how well yours will perform is to have it load tested.