RE: FROG 149 Vibramatic
Fiery, you mention the wrong prop nut. Be advised that many engines were sold with a normal hex. nut, but there were also quite a few with a nice spinner nut, like this one of mine.
Another point is that the "name" "Frog 149" is only on one side of the crankcase. The other side is plain. They're nice engines, really good runners.