There are only two applications for the DE suffix that could have "F" at the beginning of the stamp.
DE 1958 283 Powrglid, air susp - - - full size/Malibu
DE 1962 283 Powerglide, a/c - 195 - A X
In 66 or 67 the Flint engine plant began using "V" at the beginning of the stamp on their V8 engines, replacing the "F". F was still used on the L6 engines.
