I'm not sure, but I think the '61 most likely uses the same rear shocks as
the '59, and you're in luck, since they are the easy ones to find. I used
Gabriel on the back, and Koni on the front, but would recommend Koni all the
way around. I don't have the number off hand, and am not even for sure if the
'59 and '61 use the same back shocks. You can put air shocks to get the rear
end up there, but the ride will suffer.
Bill '59 Crown