they came off of a "G Rides" '67 Notchback. I got it at walmart....
there were 2 then but i just bought one of them. Now after searching all the other stores and even toys'r us......i can't find another.
In fact, in that series, there is a old bug. it would look good with your set up, because the fronts are those sizes that i have, and the rears are a little bigger.
But as of now, the only place i've seen them are on e-bay.