Since the smoking tire LS400 finally hit 1 million miles earlier in the week this popped up on Jalopnik
Interesting question and many different ways to think about it. First I guess would be what cars could make it 1 million miles... not too many.
There have been documented cases of Lexus/toyota V8's in the UZ range making it.
Same with GM LS motors.
Cummins diesels have done it
Duramax engines have done it
Older Mercedes diesels have done it
etc......
Dreaming I'd enjoy driving an early 00's S8 manual for that many miles, sporty, manual, comfy, luxury, good in all weather conditions we get around here but at the same time there is no way that thing is hitting that many miles without a ton of money thrown at it and even then I don't think the motor would make it.
A 100 series cruiser could make it on the original motor but most likely not if it is used off pavement in "severe" duty a bunch. The UZ motors that have made it that far were almost always traveling salesmen type people that drove it on road all the time and religiously did maintenance on it.
My LS430 could make it but I do find myself always wishing a manual was in it after being in it for too long.
Sports cars are most likely thrashed on too much to make it although i've seen a LSX corvette with almost 800k on the original motor.
So the question is what car could make it that many miles on the original motor but would you even want to do it as most likely the ones that can wouldn't be the most exciting 1 million miles and really to hit that many miles it would have to be your only mode of transportation every day for long wheel time.