Difference between?

What is the difference between the B & S 11 HP engines below? I have the first one in the list on a JD 111. It is the original engine and now needs to be rebuilt and have the governor repaired. I thought I might be able to get another engine and have located the second one (used) in the list.

Model 252707 Type 0644-01 Code 82092911
Model 252707 Type 0620-01 Unknown


I also looked at smallengineswarehouse but they don't have an exact replacement either. Their webpage says I would have to use parts off of mine (stator, etc. since I have an electric PTO) and it is almost $500.

Thanks

BTW, which model/code/type would I need if I was looking for a 11.5, 12 or 14 hp replacement?

 

You can download the IPL and compare parts between the 2 engines.

http://www.odref.com/briggsandstratton/model-25/252700-ms6929-0602.pdf

Glancing over (quickly) the IPL, the only thing different that stuck out to me was the carb. It appears to use the same crank (depending on date codes of the engines)