See pics in gallery "743 block heater". Installed in 2nd freeze plug from the front on the right hand side. Kubota 70000-00297 (Block Heater Kit) It comes with a stand off bushing so it clears the cylinder wall.
Several years too late, but maybe helpful for the next guy... I ordered the Kubota 70000-00297 Block Heater Kit (Messick's has it for $66.48) and all is well. It comes with a standoff bushing so there's no interference with the cylinder wall. See gallery "743 block heater" for pics of install in...