On my RV-9A I put in a 1991 Lycoming O-320B2C from a Robinson Helicopter. It had a hollow crank and was easy to switch to a CS with the pump bolting up, line to the front and the rear crank plug added. The other challenges were it had a conical mount so the motor mount was a special order from Vans and I had to change out the sump and intake to move the aft carb to the middle to get nose gear clearance and add a fuel pump gear and pin in the rear accessory housing.
Scott- 2018 dues paid
Got medical back, now building a 7A; N579RV reserved, new engine installed, doing FWF, instruments & finish painting.
RV-12 #120515, N319RV 1st flight 12/2015 now over 270 hours.
RV-9A, 536 hours sold, RV-7 sold, Kitfox sold