How many different versions of the Holley Vaporizer data plates exist? I have three Vaporizers and they all have unique data plates. One is made by Ford and has Ford casting numbers on it. Of the two made by Holley, one has a serial number and the other doesn't.
I called three of the vendors that I have dealt with in the past (Langs, Chaffins, & Snyders) to find out if they knew of any of the differences between the data plates. None of them had seen the one pictured at the bottom with the serial number on it. The closest explanation that I could get was from Stephen Lang. He thought that the Holley data plate with the serial number was issued specifically for manufacturers of aftermarket manifolds, like the Altas one pictured above. He didn't think that there were any records on file at the Ford archives in regards to those with serial numbers, but did suggest that I might get more answers there.