I have an FEJ 12127A2 57 tach-drive distributor. The distributor body also has H 721. Someone has identified it as a replacement 292 distributor. The A indicating 292, and the 2 indicating replacement. Could H 721 be a date code/w H representing the month of August, and 721 representing year (57) and day (21)? No doubt it's a 57 distributor because a 55 cap won't fit, and the advance springs are not visible as found on 55-56 distributors. 

The distributor was on my 55 T-bird when I inherited it, along with the original 55 Teapot/w divorced choke. I don't know if the carburetor was modified to work with the 57 distributor. Although the car has been in the family for 50 years, I know little about its history. I rather doubt that my dad knew. Unfortunately, having passed away in 2012, I can't ask him. 

Would Ford have used a 57 replacement distributor in place of the 55 Loadomatic, if the Loadomatic was defective? In other words, did Ford continue to manufacture Loadomatic tach-drive distributors after the 56 model year? If so, why do I have a 57 distributor? 

I realize that a lot can happen in 66 years. In addition to the distributor not being correct for 55, my block was manufactured in 56. The heads, manifolds, and carburetor are all correct for 55. Just another one of life's mysteries.