I don't know about a Datsun, but a Subaru will work.
I backed off finally and cruised into Montana, where I was informed that I'd gone directly by the Wyoming State Patrol academy where they routinely set speed traps to give the new officers some experience. And that I could have ended up in jail for the, ah, slightly over the speed limit rate I was driving. All I will say is that I honestly don't know how fast that was because the speedo didn't go quite high enough.
I still have the car. If I tried that on the roads around here, though, I'd be dead meat.