That swap meet motor doesn't sound like such a good deal to me, but I'm not an expert on them. Whizzer has their own club (whizzer motor bike owners) where you could find out more info. This motor sounds like the left overs from another bike restoration.
I had never seen a whizzer in real life before I went to Portland last year. There just weren't any of them around here when I was growing up. I had always assumed they had 2 stroke motors until I actually saw one.
I wish the Simplex motors had been more reliable (read ability to take abuse) so there would have been more survivors. I think this is why Cushman & Whizzer outnumber us by such a margin. Those 4 stroke motors could resist teenager abuse.
Mike Sal