Does anyone know the measurement from the ground to the bottom of the pinch welds from front to back on a 66 San Jose fastback with 289? I am looking for the actual as built specification from Ford.
Don't believe those were ever specified in any document from Ford. Appears to be just not the point they cared to used for ride height or other purposes. As mentioned only one I've found over the decades was the wheel well (top of wheel well) measurement and believe those measurements were posted in one of the first threads on this site, in an article I wrote for Mustang Times and other sites around the internet twenty plus years ago
This is a Shelby with 14 x 6 wheels and 6.95 x 14 Goodyear Blue Streak tires.
Might try adding or subtracting half the difference in the height between those and the factory Mustang tire. Even if you don't go through the math the basic measurement is going to be close