: with standard gearing & tires - : About 2200 at 50 : About 2000 at 45 : Idle = 100 - 250 rpm ballparky.: Bob Carabbio With standard gearing and 19" wheels: 2400 rpm at 45mph 2600 rpm at 50mph Idles at 800rpm with spark advanced 500 rpm with spark retarded. I have a 6 volt tach in my 31 coupe, and that is what it reads.With 21" wheels it would be about 150 rpm less than what I stated above.Gas engines cannot idle at 100- 250rpm.They don't stay running much lower than 300-400 rpm.Running a Model A engine lower than 500rpm is hard on it due to its splash oiling system.It would not get enough oil into the cylinders/pistons at a low idle speed. Greg
|