Hello tclederman, the engine has the number 3835258, it is the engine that came new with the truck. The sales receipt has the date of May 24th, 1948. I wasn't very clear in my initial inquiry and didn't mention that the 1947 and 1948 wiring diagrams are identical except for the ammeter wiring. The wires would not allow me to wire it the way the 1948 schematic showed but everything was perfect for the 1947 schematic. Here are the differences : http://s23.photobucket.com/user/littlebuddytoo/media/48Chevy/Ammeter.jpg.html
So this ammeter configuration may simply remain a mystery! Thanks for your help!

Last edited by littlebuddie; 07/23/2015 6:56 PM.
1948 AD Pickup