Ford shelby part?

[EdwardGT350]

is this a ford/shelby part?

[Coralsnake]

Probably not an original part without any Ford markings on it.

[Bob Gaines]

The marking indicates that it is a aftermarket part. The factory 66 part would ether be marked with a KS or FOMOCO in the oval in cursive. Later versions trademark evolved to the FOMOCO in block letters inside a rectangle. The base on a 66 version was square shaped . The shape changed to hex shape base 67 forward.

[EdwardGT350]

more pics

[Bob Gaines]

more pics

In this context J4 probably means sept of 1974. A aftermarket part put into a genuine old box IMO. It wouldn't be the first time.  

[rhjanes]

I believe that mark like two boomerangs, is the "Standard Ignition" parts mark.  I could be wrong.  It was the 1970's when I last worked auto parts, but it looks familiar.   Back in those days, those were good quality parts, but not factory.