My plane was the retract version and I modified it so there was no mounting block to begin with. The entire underside was sheeted with balsa. I cut it all out (from the firewall back to the former at the front of the wingsaddle area(I'd call it F3) and glued in a plywood bottom. I then drilled the new ply plate and installed blindnuts. As Tommy said I did not move the gear forward any as the wheel placement was falling more forward than the original retract wheel location and the plane landed soo well with the retracts that I was attempting to get the placement the same. I just got extremely tired of bending retract struts.
Eddie