While I do understand what you are saying in regards about a week's difference in the B/D's, there were special circumstances which led me to believe that there is more to it than a build date and vin #. When I was at Jenkin's shop back in 1993, he showed me a confidential file on the L78 program. I was allowed to copy some of the dealer invoices from his personal cars but he was reluctant to let me have copies of this file. Maybe because they were confidential GM files? I don't know. I was there and I know what I saw, and I have no reason to make this up. Also factor in that I logged a lot of phone time with Paul Prior back in those days and much of what Paul told me was echoed with Jenkin's comments. For those who don't know, Paul Prior was an engineer who worked with Vince Piggins during the 1950s and 60s and was very involved with high performance cars built during the 1960s.
It is a well known fact that most factory high performance cars were built just for certain types of motorsports. Z28s were built for trans am racing, Super Birds were built for NASCAR, and so on. If you look at the history books, many factory hot rods were built for just drag racing..........and the 375 horse Camaro was no exception. Couple that with the ZL1, Chrysler Hemi cars, Ford Thunder bolts, Z11 Chevrolets and so on. The main agenda with the L78 was for NHRA. I'm sure that working in concert with the Pace Car program was also a factor at that time. But remember this, GM was not going to sell a lot of 375 horse Camaros by having two pace cars go around the track before the 1967 Indy-500.
What GM and car enthusiasts wanted during the late 1960s was to see these cars perform at the race track, and win. And winning at big NHRA events was what it was all about back then too. Do you not remember the slogan "race on Sunday, sell on Monday"? Many dealerships used this to sell HP cars. There were about 55,000 people who attended the 1967 NHRA US Nationals, so even if you're not a big fan or historian of drag racing, it was a big deal to win this race, just as it was with any of the other types of motorsports back then. Look through many of the old hot rod magazines from the 1960s. That "drag car" of Bill Jenkins was in just about every magazine back then! Were there many articles or ink on the 1967 Indy Pace cars?
I am surprised at your comments about Bill Jenkins. He was much more than a drag racer. He is a living legend in motorsports. Jenkins was a racer, an engineer, an engine builder and he worked with GM for many years in R&D. I think many on this forum will agree that there is probably no one who did more for the small block Chevrolet than Bill Jenkins. Couple this with all of the FACTORY sponsored high performance clinics that racers such as Bill Jenkins, Dave Strickler, Ronnie Sox, and Buddy Martin put on during the late 1960s. I was there! It was people like this, along with factory backing that helped sell these cars to the younger generation! So, if you think that building a car for NHRA with the help of Bill Jenkins is a little hard to swallow, then it's my opinion that you are extremely misguided, and lived in a shell during the late 1960s.
John Z, can you add anything here to what I've written? You were there and can maybe add more to what I am trying to say here.