Topic: 67 San Jose Running Change Thread - Rear Valance Changes

[67gtasanjose]

Should we possibly start a discussion (new thread) and perhaps a survey of what may have occurred to bring about a whole new engineering number for the change from EXTENSION ASSY, LOWER BACK PANEL (a.k.a. Rear Apron) number(s) C7ZB-6540544-A(B) to the number(s) C7ZB-6540330-A(B) ?
I understand an EARLY version of the Quad Exhaust tips (without dimples for clearance to the shackles) was another issue in early production but that could be yet another topic...but clearly (it would appear) the rear Apron WITH cutouts was in the works ahead of this 12-15-66 date on Jim's copy because there were two engineering numbers (-A & -B) that were superceded.

We apparently have different copies.

On the back page of the book is the only "publication" date I can find - 1995.
Jim

My outside, back cover page is Copyright ©️ 2009

Ok, we have different literature.
The page 63 Jim has on hand has more information on the Effective Date of an Engineering Number Change to the Rear Apron that looks to have a Running Change of sorts so back to that aspect of the discussion.

[jwc66k]

Each Ford design engineering group had total custody of its base number assignments. (At Ford Aerospace, we called it "creative part number engineering".) When a different design was introduced for a part, in this case the "Lower Back Panel" (we call it the rear valence) a new base number was used. We don't know all the intricacies involved here, but 1964-66 Mustangs used base number 40544, 67 Mustangs used 40330, which was then changed to 40544 in a design change scenario. It's not unusual to change base numbers, Ford did this a lot (yes it is two words) in the transition from production parts to service parts, mostly to consolidate similar parts. They understood it and made it work. Just believe.
Jim