500k can be done indeed. I worked on 50 year old air planes realizing I was getting owned by the scale of what car markets put upon a dumb populus..
Today, I go as far as welding structures, realizing all replacement parts are better than oe, and even rebuilding engne components is better than ever.
Starting with a good base takes away alot of frustration of course. ie: the diesel at low rpms goes a long day breaking the body, but the gas engine keeps the body and breaks the engine.
alot of things to hang onto.
I even took a subaru until breaking in the middle, losing hopes of accurate measurements to fix.. it was 17 and 167k miles, no repairs. It stangely stayed looking good, the rust game is nasty. Just checked fluids once and awhile. Gave it away running perfect...a 3 main bearing extinction for free.
