Yup, have a io-340 in my 9a, 230 hours in the past ~9 months, great power plant. Dual pmag, AFP, etc. I used the stock vans ff-fwd kit and it worked fine other than the throttle/mixture bracket which did not fit. I ended up using the AFP bracket base with some custom-made steel offsets.
I have an OX-340 on my -9A and used the standard O-320 baffle & FWF kit without any problems. I had to make a new FAB as the Rotec TBI is shorter than a standard carb, but that is the only difference.