I had a 1996 Corvette pilot car, notice the low vin. If I remember right every model year the stopped the year prior assembly line to build the following year car to see if anything had to be altered. Look at the build date April of 95

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Found another Zora pic w/ same "68" Mule but more of the car showing, likely taken the same day?
It may be a modified Midyear w/ '68 style bodywork as Bill noted, A-Pillar + W'shld. looks '68 also rear roof coupe angle but length of body line kick up at door handle more like a modified Midyear Door?:hmmm:
Is this the Red Mule w/ ZL1 M40 or another car, love to hear more if anyone w/ info to share.
:beers:
~ Pete

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Not quite.

Typically by the time you are ready for assembly plant involvement you have already been through a couple rounds of stationary builds ("prototypes").

Current production build would continue at the present line rate; the future model year pilot builds would be introduced one at a time, and perhaps with an empty carrier in front of and behind the special build, to provide a little cushion. The new model launch team (engineering, mostly, but also program management, and the other disciplines - purchasing, containerization, logistics, quality/reliability - would also be on site) would follow the build through the process making note of any issues or problems for resolution. There is, of course, cross pollenization and sharing of learnings between the various assembly plants as well, as the model year is rolled out.

Usually there would be a couple iterations of this, one earlier and then a second right before model changeover, typically for each affected assembly plant.

By way of background, the "prototype" and "pilot" designations have been replaced with the more descriptive terms below:

Mule - hand cobbled stationary engineering build; can be from the same platform or even a different platform. For example - M/L Van (Astro/Safari) mules were built from chopped down Suburbans.

Integration build - engineering activity using cobbled or fabricated design intent parts, in the experimental build facility (GMARC, or Truck Validation Center, or at the GM Tech Center). These will be the vehicles used for overall development (ride/handling, squeak and rattle, ergonomics, powertrain, etc) and full vehicle durability/validation.

Manufacturing build - Non Saleable: assembly plant activity using unvalidated design intent parts, built down the assembly line. Vehicles have experimental VINs and cannot be sold to the general public. These are primarily for assembly plant practice, but the vehicles will go on for continued development and validation work, as well as some show duty and maybe early Captured Test Fleet usage (allowing the program team members to get exposure and normal usage miles).

Manufacturing build - Saleable: assembly plant builds using fully validated design intent parts off production tools. Vehicles have production VINs and can be sold at the end of their internal usage even though they are pre-production units. More assembly plant practice, with final refinements, show usage, and Saleable Captured Test Fleet usage.

Start of Regular Production - the real deal.

I mention all this because there has been a move to introduce the assembly plant earlier and earlier in the design process, turning what had previously been a slow, methodical, learning event into a mass production activity. I spent the whole summer in Wentzville (St Louis) one year building Integration level van bodies down the assembly line. Prior to that it would have been unthinkable.

K

A couple quick thoughts about model change over:

Usually the assembly line at a particular plant will shut down completely for retooling or upgrades, as one would expect. This is fine, because you start with the "lead plant" first, and the other plants continue to produce the current model until it is their turn, so you still have product in the field to sell.*

However, if there is not a lot of product change the program team can elect to do a "rolling model change". The line does not shut down and the new model follows right after the current model, sometimes with an empty carrier but sometimes not even that. During the squarebody era there were a couple changeovers where the only difference was the new truck had a handmade paper sign taped to the windshield; that was the only difference discernable to the assembly line workers.

There were a couple occasions were the VINs didn't even start over; they just continued to ratchet up sequentially based on the prior year's starting point.

K

*That is what is so remarkable about Henry Ford's transition from the 1927 Model T to the 1928 Model A. Ford shut the Highland Park plant down cold while they designed and tooled the new model at the Rouge. It was quite the media sensation when the Model A was finally introduced.

By the time 1996 rolled around I had already worked at Chevrolet Flint Assembly and on the production launch team for 10 years, the Milford Proving Ground (3 years), the GM Desert Proving Ground (4 years) and had moved on to my first Design/Release position as the Engine Air Induction engineer for the GMT800 program (1999 model year introduction).

Many of those air induction parts are still in use today.

K

Most of the time, there are model year changes. It might just be a small harness change or a new supplier. Some programs don't like running changes and save them for the new model year.
In one of the plants, all the new models were white. Really easy to tell them apart that way!

----And you still can see the 65-6-7 door panel on the passenger door!.....Bill S