Well... after researching a little more, I think I have found that this is not the original engine. The casting number on the engine is 3921968, which according to this site: http://www.inliners.org/casting/numbers.html

Which makes it either a 230 or a 250 and is from 64-76. How do I tell the difference? Does the Rochester Mono Jet belong to that engine?

Sorry folks, this is all new to me so I do appreciate the help.