According to John Mummert's site (ford-y-block.com/Technical-Distributors), FEK distributors were made for 57-59, have both vacuum and centrifugal advance, and use ball bearings (not hinge) for breaker plate. 

Follow Teds advice to determine if you have a 54 - 56 distributor. However, I believe FEK 12127 A is a 57 dual advance distributor if I can remember correctly.


64F100 57FAIRLANE500

1954-1956 FYB engines used a Ford-O-Matic distributor.  The cap, rotor, and points are specific to those distributors.  As mentioned above, the distributor cap is smaller in diameter than the 1957 and newer distributor caps.

The ’54-’56 FOM distributors are recognizable by the advance springs being located above the points breaker plate and the breaker points being the ‘straight’ style.  The 1957 and newer distributors have the advance springs under the points breaker plate and the points themselves are the ‘curved’ style.

Lorena, Texas (South of Waco)

Thanks for your response.  This is not on a tach drive style dist.  It is a FEK 12127A on the dist. does not have a 1 or 2 after the A

The 55 Tbird distributor cap will not fit a 57 Tbird distributor. The 55 cap is smaller. Other than the tach drive for 55-57 Tbirds, I don't know that there is any difference between models. 

I have read that there is a difference in the 55 & 57 dist. cap and rotor.  What would that be? How do you tell them apart?  Been having tuning issues and question came up. Not on a tach drive style dist.  It is a FEK 12127A on the dist. does not have a 1 or 2 after the A