Sam,  Airchaser makes a series of blowers for outdoor/indoor
inflatables, from 1/4 HP to 3 HP.  Each model has increased output
in both cubic feet per minute (CFM) and inches water gage pressure.
Select the one that fills your needs.

Organ pipes are typically voiced at 6" wind or less, although
fairground organs do go higher, but I would not think over 9".  CFM for
a voicing chest is moot -- you are only playing a few pipes at a time
so very little air is needed.

These blowers run about $150 and less.  That's a lot less than an
official pipe organ blower which runs closer to $2000 and accomplishes
the same thing.  Here's the link.  I think you can order them through
Amazon.  Check around for vendors and prices.

https://www.airchaser.com/en/high-static-inflatable-blowers/ 

Jim Quashnock