Hurrah!

[AtW]

Odometers should be cryptographically paired with the engine ID - done once at the factory and a public website allowing to verify the matches.

Additionally anyone found to be clocking cars should be beheaded.

[Troll]

Presumably you have only TP insurance on that age car... any Insurance companies/brokers you can recommend?

[Swamp Thing]

Yes, but suuuuuurely its possible to assign unique number to the engine and use it as public key pair to encrypt checksum on the odometer, this way if engine is changed then its obvious that odometer lied.

It's actually easier to change mileage on modern speedometers. With analogue clocks, a trained eye could tell when the dials had been moved. But with digital/LCD displays, it's a simple 'reprogramming' trick. There's no connection to the engine.
Or put another way, look at the phenomenal growth of the 'mileage correction' specialists out there...