Crankcase Difference 360 and 390 Auto's

What is the physical differences between the 360 Auto cases and the early (pre80) 390 Auto Auto cases ?

As I don't have a 360 to look at, I would be interested to know the difference.

In other words .... how do you tell them apart ?

The 360 cases are not machined out enough to take the slightly larger 390 fly wheels.

By flywheel Steve, I take it you are referring to the two crank webs ? Or the Motoplat flywheel ?

Crank webs, I tried to put a 390 crank into 360 cases, took me an hour or two to work out what 1 was doing wrong, it did not help both engines I was building had lost their engine number plate.

Thanks Steve. I will order a 360 and 390 centre gasket to measure the difference.

I always tap out my own gaskets so that would not have helped me.