66Engine size

[Poppy Red]

I recently purchased (another) 66 T-Bird. Was told the original 428 Q option engine was damaged, and a later Cobra Jet 428 was installed. Cannot get any valid info on the engine from the guy I purchased it from, but from info from the 428 CJ web site, I have located the casting stamp date. It looks like 7C31, which would translate to 1967, March 31. Can any one confirm this, and if so, the engine cannot be a 428 CJ as they did not cast them until 1968/9, I am told. Is it possible to identify (from the outside) if this engine is an actual 428, or a 390?

Other casting numbers from the lower/underside left bank are "24 D1F, and from the lower/underside right bank, "C7ME-A

 

[captrick]

I think that the "Q" code 428 was only offered as an option in 1966 as a police car. In 1967 the "Q" was an option in a Shelby spec car and a police car. The 428 PI stands for POLICE INTERSEPTOR.