C15963 Pulley UPGRADE KIT (Center Drive) for 38"/40" J, K, L,M, Case Ingersoll LEFT Hand Discharge Models and Rear Discharge. This is the TOP Drive Pulley for the belt from engine PTO. 
For all J, K, L, M, N, 38-40" models/cutting width. But many use this pulley to increase blade speed and performance on 44"/45"/46"/48" Left hand discharge decks.
Our new  pulley replacement kit included both style keys for the spindle. But it includes our custom made spacer/riser To raise the pulley up a little bit so there is less of a angle on the belt when deck is in mowing position for less wear on the belt and pulley.
 
This kit works on all mower decks used on Case Ingersoll 200, 400, and 600 series tractors that have the discharge chute on the LEFT side or rear of the mower deck.
Do not for get your new PTO drive belt and deck belt
 
NOT FOR 60 INCH MOWER DECKS. NOT FOR RM RIGHT HAND DISCHARGE DECKS.
NOTE- Color or finish may vary.