Tony, an interesting post, which begs some questions.
The 4K car that is in question, I believe, was one of the Display cars that could have been found at the Indy Museum or at the Murat Temple.
I have verified that at least two display cars were delivered to Indy. Just as today, the Museum always displays a mocked up Pace Car.
What leads you to believe that an L78 car would have been one of the display cars and not an L35 car?
Couldn't this L78 have had other potential uses at Indy?
It is the first time in Indy history that the Pace Cars were considered modified. Although, not much by today's standards,but nevertheless modified for the day.
Do to Speedway rules for Pace Car qualification and Chevrolet's hasty effort to debut to "the Industry" the NEW L78 motors in the Pace Car, these cars had to be changed into the hybrid animals that Charley and the Clarey's have today..or more like what just Charley has today.
I'm not familiar with any requirements that Indy puts on pace cars. Do you have any documentation on this?
Are you saying that due to Speedway rules, the L78 couldn't be used? This I find hard to believe, since the L78 was a widely available RPO by May.
The original third car was made into a test mule as stated by Phil. The fact that an L78 could not of had a automatic in 1967 is only true for public sales. The Chevrolet Proving ground Mechanics had the inherent problems that existed when mating a L78 up with a Turbo 400 worked out before the end of the first day of Pace Car trials. The only stated reason for the L78's being pulled is because they made a "Terrible racket" as described by one of the Indy Zone managers that I interviewed.
There is the practical issue of making the L78/M40 combo work, but on a higher level, Chevrolet may have chosen not to use a non-available powertrain in the pacers. If the issue was solely a noise issue, then why not use a L35/M20 combo? It would have only required swapping out the engine.
So when it comes to the car that Jeff is talking about, which I believe to be this car (or one just like it). The "System" had already had it scheduled to be a L78, not for Pace Car duties, but to show it off to the ever pressing crowds that visit the Indy Museum and the Murat Temple at this time of year, the NEW L78 motor available to the Camaro.
This is stated as fact. Is it or is it the current working theory?