Evinrude identification

[Fishhenge]

No doubt this has been asked before, but here goes again anyway. Can anyone point me in the direction of a good site to decode the model number and serial number on a 50s/60s Evinrude outboard? there seems to be lots for newer outboards but I haven't found one for the sixties models and I need to order an impeller for one. The numbers (I think it is a 40hp) are 40302D and C384985. Any info will be very much appreciated!

[Rapier]

Model 40302 is a '63 BigTwin 40hp

http://www.old-omc.de/e_1963/seite_1011.jpg

http://www.old-omc.de/start.html