gen/water pump/fan belt

[19Fordy]

Do this:
https://www.bearingboys.co.uk/Fan-Belt-Calculator-22-a

Or use a piece of rope wrapped around both polleys. EAB engines used 2 narrow belts. If you have an EAB engine in a 39 Ford, it has probably been converted using 2 wide belts. One that goes around the generator, 2 truck water pumps and crank pulley and another separate belt for the fan pulley and crank pulley. It would look similar to this 8BA set up in a 40. The numbers shown on these belts were selected to fit this custom set up only.