Yes it has been done, notably, Outlaw Engines, who does mostly airboats in Florida.
I have a T-18 with a low time, upgraded O-290-G that I would bore the cylinder spigots to fit O-320 cylinders, just to keep the special engine mount.
Plus, I think it would be cheaper than finding O-290 piston rings.
I have access to a milling machine, and plan to do it myself, otherwise, I would generally say no.
Even if the dollars made sense, the amount of time you might consume with the modification would be directly subtracted from flying time, always a bad choice.
