I'm a new user here.... I have a 351 engine with harmonic balancer # C8OE-6318-E1 ( or could be C9OE-6318-E1). Can anyone tell me the year and vehicle origin of this motor??

 

Year sorta but vehicle no... Ford parts aren't quite identified that way. The casting number tells you when the casting mold that part came from was created and what division paid for the mold, but that's about it. In this case "C8" and "C9" are '68 and '69 "O" is Fairlane/Torino and "E" is engine. In the early days you are pretty safe in assuming engine parts were used in the same year and vehicle for which they were cast but leftover parts will also find their way into other vehicles and later years.

 

Thanks Paul ... I needed to confirm that the balancer was correct for my '69 block. I'm having a real problem finding crank and water pump pulleys that fit(don't contact each other).

 

I had the same problem when I was switching to single pulleys on my 1969 351W. There was about a sixteenth inch interference between the crank and water pump pulleys I had on hand.
I visited a local junkyard which had a big bin of pulleys for five bucks each, and luckily found a suitable one.

If you have a choice, reduce the size of the crank pulley to slightly "underdrive" the accessories.

Or if you felt like spending money, it would be easy to rationalize buying a set of underdrive pulleys such as those from March.