electrical failure on a 1975
Don't just replace the fusible link, its the gauge that is the problem, work around it. Full current for 40 years on anything is going to take its toll. That gauge is down right dangerous, good thing it didn't take anything else out.
Here is the fix so that doesn't happen again.
http://www.madelectrical.com/electricaltech/amp-gauges.shtml
Enjoy!