I suspect on the theory of the last digit the number of seats they would have had problems with the duplication of models. I can't see a viable recip single short of a big honkin radial being able to seat more than 8 - even that big 8 cylinder IO-720 I don't think would be able to do it.

That was just some of the info I remember from the magazine article. By the way, wasn't the early 210A a 4 seater?

Hogflyer