[Mgs] Engine ID again

[Tom Buchanan]

First off, thanks to Eric, Phil, Max and Paul for identifying my spare 
engine. Now, the engine that is in my 1974 (chrome bumper) GT does not have 
the engine number tag on it. Some previous owner removed it. And I do not 
know if it is the original engine. Can anyone give me clues to look for so 
I can identify this engine. At one time it did have an air pump. The Timing 
Chain and Sprocket are single row.

Thanks again,
  Tom