...Good Morning.
The Standard 'Hub' height* for the standard 351C Water Pump is 5.75", the Height of the 351W 'Shorty' Pump is 4.25". Hense, 1.5" Shorter. See pic. For the purpose of eliminating the 'Hump' on a Pantera, the Alternator must be mover back 2.0" and the Original WP Pulley must be moved Back 3.0". With the Shorty pump taking up 1.5", and my plan to raise the hatch mounting surface on a 1.0" Square tube frame, leaves a Clearance Discrepancy of 0.5". I will deal with at the time of the test fit.
*Hub height is taken at the Face/Mounting Surface of the Pulley. pic included and there is this: (the 351W Shorty WP is Listed as a '302-
351W')