It's a HD Stellite Valve engine on a 2" Homelite Trash Pump. Would also like to know HP if possible.
It is definitely an old style engine with the fuel tank hanging off the carb (carb is that long thin aluminum horizontal body - does not look like a "modern" carb like on a Honda.)
Type no. is what designates that the parts actually fit that particular engine. The code no. will also do this it will use this part no. to a certain serial no. and a different one after that serial no. code is year 1984 month 05 may 10 day of the month 06 assembly line I think