You might check with these folks for your air shut off.
http://www.powerlinecomponents.com/partscat.htmIf you need I can send you some detailed pictures of the shutoff on my 6V-53. It sits right on top of the blower and is spring loaded. The other 6V-53 I have came out of a military APC and uses Halon gas injected into the intake as an emergency shut down.
Sounds like you had fun getting it unloaded without killing yourself, been there myself a time or two. Recently bought a 4000 lb. forklift off of Craigslist for $900.00, should have done it years ago.
