I thought you would appreciate the VW reference, Trev. My first car was a 1500 Beetle. Great car, but not as reliable as the 1300. Mine was 12 volt. It used to sit on 70 mph all day. Wouldn't go much faster, didn't like hills, took about 6 months to get to 70 mph.
I did have it "off the clock" (about 90 mph from memory) one day on the Newell Hwy, passing a semi-trailer. It didn't like it, and it let me know, shaking, weird noises. I backed off to 60 mph and let it cool down a bit.