Hi all,
Thank you for your input. Together we are smarter when we work together.
Below is an image that I have been able to piece together, with your help, to illustrated what appears to be the evolution of the 65-66 Mustang fastback vent drip tray water management. There are three configurations.
Configuration 1 would appear all 1965 Mustang fastback, including 65 GT350's and likely the first 252 66 GT350s with a drain tube and no water shield.
Configuration 2 is where I am having problems figuring out the time period. Maybe very early 66 Mustang fastbacks. It is a transitional configuration and may not be very many cars. It has the provision for a drain tube, but not tube and has the water shield in place.
Configuration 3 appears to be most of the 1966 fastback production, because of the image posted earlier with absent drain tube fitting and water shield in place, the poster says it it an October 1965 build. This is near the front end of 66 production. The February 1966 Mustang fastback I own also has the absent trip tray fitting, but the water shield is long gone, but had to be there to manage any dripped water.
Relevant to the 1966 GT350 production, excluding the first 252 carry over cars, it is indeterminate if the water shield was a delete item at the San Jose plant or Shelby American removed during the side scoop ducting pieces installation from inside the car, requiring the interior and quarter panels to be removed. The water shield would have been in the way and likely removed then or was not installed at all.
Now near the end of the 1966 GT350 production, there is one example of a 66 GT350, May 1966 San Jose build in the last 150 GT350's to be built, that still had the water shield in place. I predict the reason is the ducting pieces, to avoid removing the interior and saving cost, were installed from outside the car through the 3+ inch holes cut into the side body and wheel well. The water shield was no longer in the way, not disturbed and left in place. At least in this one GT350. The current estimate of SAI VIN's for outside ducting pieces is between 6S2022 to 2077 to the end 6S2374. Based on one GT350 data point, it would appear that the water shield may not have been a delete item and was removed by Shelby American on the first 1769 to 1824 GT350's (does not include first 0252 cars.) That also means there are near 297 to 352 very late GT350's that could have been built with water shield retained in place.
Until more date is collected, these are just estimates based on the limited data. As more date is shared, adjustments can be made. Anyone with more info to share?
I hope that helps.
Cory