I've had two engines modified from conical to dynofocal, the O-340 and a
0-290G in both cases Ajax (ad in Trade-a Plane) did the complete mods. I
think they weld up the conical holes and then recut them in the dynofocal
configuration. There are two different dynofocal configurations as I
remember, but I can't remember their designations - it has to do with the
focal point of the mount.
I think the biggest problem fitting a 235 with a O-360 is the carb. The
standard carb hits the nose gear fittings. I tried a smaller SPA carb which
fits but Ly-Con could not get the fuel distribution even or even close over
all power settings which resulted in high CHTs on some cylinders when the
power was reduced. Finally I converted to fuel injection and all is fine
now.

Rusty