Your truck is actually a GMC 4000 series "L" model Tilt Cab. Check out this link, http://www.6066gmcguy.org/Lmodel.htm The GMC "P" model trucks, were called Forward Control.
I was checking that site out earlier, Lots of information. In my experience when you drive from in front of the engine that is a forward control design. I didn't realize that GM made a model known as the forward control. sorry for the confusion
