This is the Wet End portion of a 4 HP Executive 2-1/2" suction, 56Y frame spa pump. This is basically a pump without a motor.
This Wet End is used with a 4 HP, 56Y frame, thru-bolt style motor. The motor used may be either a single speed or a two speed. The Wet End may be rotated 90 degrees to change the discharge position.
The inlet is standard 2-1/2" buttress and outlet is standard 2" buttress threads. See below for exact dimensions. This has a center inlet and side discharge.