Early WR
Note abscence of vertical magneto mount holes

Inside of WR
Note big machined holes for cam ball bearings

1950-1951 WR
New casting
For vertical mag mount only

Inside of KR cam cover

Early U "replica" cover
Made from WL cover. All fins cleanly removed

Late WR "replica" cover
Made from WL cover. Fins removed in gen. & dist. area.