[jb-ob]

Jim,

From here you will need to get serious documentation.

You need a copy of the 2005 article about the car. The evidence you need might be in the back ground of any pictures taken.

Unfortunately there is nothing unique about your Deliveries' chassis. Even if you lifted the body to expose the frame number (matching the engine??) it is still a common chassis used under any Ford car May thru November.

You are loosing me when you say the body is nailed to a frame. FORD never produced a car body with a wooden sub-frame. His sub-contractors did, Briggs & Murray.
Most production Deliveries have a skeletal frame onto which the rear door skin is nailed. The metal quarter panels are also nailed to a wooden frame surrounding the rear door providing support. The remaining body wood is to support the roof bows & rain gutters.

One has to wonder where a May '28 chassis sat until being used, say in September for your Delivery body ??

A more likely event was Ford contacted with Budd (Philly) to build a small body Delivery from the dimensions of their Tudor sedan. To accomplish this a complete chassis (yours ??), fenders, cowl, & Tudor sedan shell (w/ steel sub frame)were shipped to Budd.
It is unusual to create only one prototype. Some can be trashed when they 'don't work out', moving on to 'plan b'. This might account for the time from May until maybe September.

One of the first Delivery prototypes with two different paint schemes was photographed in front of Ford Engineering, Dearborn. From there yours could have been displayed at a Chicago auto show before being sold.

This is my best guess.

jb