Is my 1966 Ford 289 motor original?

[jarconco]

I have a 1966 "A" code Mustang, does anyone know how to identify the engine block? I would like to know if it is original to the car. It appears to have this SN stamped onto the top of the block behind the intake Manifold: 8T1oo441, It may also read 81188441? It's really worn. Thanks!

[Guest pfloro]

Hello Jarconco:

The block casting # is cast into a pad located on the block near the starter motor. It believe it is obscured by the motor. This will only tell you the year that the block was cast. For a 1966 289, it should read: C6?? (C= '60s decade, 6= year within the decade, ??= can't recall)... I believe that an 'A' code 289 is not externally different from a 'C' code 289. Different pistons were used to increase the compression ratio from 9.3? to 10.0. I also believe that the camshaft has a little more lift and/or duration. The 4bbl intake manifold and Autolite carb completes the 'A' code engine. If you haven't joined

the Vintage Mustang Forum (www.vintage-mustang.com), do so. The folks there can

definitely clarify and expand upon what I have stated.

Back in '66 (at least at Ford), the VIN is NOT stamped on the block so it may be impossible to know if your engine is the one which was installed as the car was being built. Also, an original engine in a '66 may have a block casting date of C5?? (1965) as a block cast in the '65 model year may have been installed in a '66 built in the beginning of the new model year.

Good Luck,

Paul

[jarconco]

Thanks for the info, Paul. I'll be sure to check out the vintage mustang site!

[A by the sea]

All the cast parts have coded dates. It has been a while, but I think it goes something like 5A would be January 1965. It is sticking in my mind that A was not January, but actually like Nov of the year before. So you would see a C5XX part number with 5A meaning it is for a 1965 model year car and the part was made in Nov of 1964. Well I hope you get the idea.

So the intake and block should be made a reasonable before the car was assembled.

If you have a K code engine then you should find the VIN stamped on the engine.