i am currently preparing to rebuild the engine in my '66 mustang. it is a 289, 4c, v8. what is the best way to determine that the engine in it now is the original engine? also, i am trying to decipher the engine id tag. finding all the information was pretty easy, however i am still trying to figure out what the engine id number means (the last number on the second row of the tag). i've found documentation listing these numbers, but there is a gap in the list. it jumps from 233 to 236 and my engine id number is E 235-S. i am not sure what the E or -S means as i can't find this in any reference materials either. also, how can i find out what the number stamped on the block means? is there one source where i might acquire this information?

 

You're about to find out first hand that the myth of a "matching numbers" early Mustang is just that. Your engine block does not have your car's VIN anywhere on it. The best you'll be able to do is find out the month and year of its production, and what car line it was destined for. Remove the starter and you'll find a series of numbers cast into the block. Compare that info against the scheduled build date of the car itself (found on you door data tag). If they're within a couple months of each other, you may well have the original engine.

I'm sure someone here will chime in with the decodings. (I can't imagine what I did with that bookmark!) Good luck and hope for the best!

 

Dan nailed it.

 

I am not as concerned as to whether or not it is the original engine because my mom is the original owner and she doesn't remember any situation where the engine might have been replaced. However, it would be nice to know for sure if at all possible. At the moment I am more curious to know what the engine id number means as well as what the number on the block means. the image is a snapshot of the info i found in a book. as you can see there is a gap inbetween 233 and 236. as i stated before, my engine id number (i call it engine id number because that is what they call it in the book i have, not sure if i am referring to it properly) is E 235-S and i'd am curious to know why it is not on this list. thanks for your insights thus far.

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