Three things to check closely; 1) The hanger "fork" the portion that slides onto the lift lever is badly worn which allows the front of the deck to droop. 2) The lift lever where the "fork" rests is also worn...has flat spot worn on it not round.
3) This affects side to side...the lift arm on the right side of the lift lever appears to lower than the left side arm.
Consider the fact this tractor and deck are over 52 yrs old...there is cumulative wear through out...it adds up to a droopy deck. It can be corrected, but will take a great deal of welding, grinding and fitting.
