https://www.caranddriver.com/news/a15339250/everything-you-n...
While the behaviour was terrible, my understanding is that the vehicles were better to drive during that era.
A well maintained diesel gets absolutely massive miles over its life, and it sounds like you’re on that path.
> My record is 82mph (UK gallons)
Do you mean ‘miles per gallon’? Either way, it’s impressive.