I have a customer that found these in a carburetor what is the correct application for these?

 D T2 on primary and F T on secondary.

Ed Jenkins

Ford Galaxie Club of America member #3350
1966 Galaxie 500 Convertible built in Chicago Illinois, will have a HIPO 390, 780 Holley, built C6, Crites Aluminum radiator, California rear floor pan, and a rust free frame from the south. Work continues.

Please visit and revisit the Carb Forum athttp://network54.com/forum/88781

Recently bought an Autolite C6ZF-E 4100 (Mustang 289 auto california emissions).
Ford manual specifies DA primary and FA secondary.
This carb appears totally original and the boosters read DT2 primary and FT secondary.
Could this be a design change for thermactor emissions control?