This is in relation to the recent vibration post.

I removed the starter to get to the casting numbers so I can ID the year/place the block was made, so I can make sure I have the correct dampener on. (There was concern that I had a later model 289/302/351 block with the earlier (3-bolt) dampener. Can someone tell me what the casting numbers mean?
1st row (smaller numbers) 6C22
2nd row (larger numbers) OC 5AE-6O15E

I am guessing that it is a 66 casted in Cleveland.

Thanks, Mike