Hi Ed
I was hoping you'd chime in, since our trucks are identical.
So it probably came with two 12 volt batteries and positive ground.
I would love to see pictures of your truck sometime as it sounds very similar to what my plan is: shorten the frame and the fire body and install a two-speed rear.
The Detroit thing is only if the 503 turnes out to be junk. Thanks once again for the info, I hope to be getting into the brakes in the next couple of months.
Tclederman, I wonder if, since they were fire trucks, they were outfitted differently