Replacing an old capacitor

A 80µF electrolytic capacitor from 1967 could be easily 120uF back then, and 40µF today. It probably had a much higher internal resistance than modern capacitors. I think any good quality 100µF 25V is okay. You may of course use 100µF 35V or higher voltage. If you still prefer 80µF, that is okay, but I really think that 80µF or 100µF does not matter.

Do you know how old tube radios are repaired ? Every capacitor is cut away and replaced, without testing them if they are bad or still a little okay.

Very likely any 80 µF capacitor you can find today rated at 25 V or more will work fine in this situation. Such a capacitor from 1967 is electrolytic, so already polarized. Replacing it with a 80 µF 35 V, for example, modern capacitor should no result in any problems.