To add onto what was already mentioned;
You can install a lock on the quadrant that allows you to raise an impliment, and then return it to the exact same position. Can be handy. A nut and bolt will suffice btw.
The hydraulic pump on the 8N is driven by the PTO shaft. Any time to press in the clutch, or otherwise disengage the pto, the impliment will start to sink down to the ground. The more worn your 8N is, the faster it will sink. This can drive you nuts when mowing.
A "fix" for the above problem is to use chains, commonly called stay chains, to hold the impliment up. You can still raise it, but the chains mechanically prevent it from sinking any lower. I've got them on mine and it sure helps.