Best that I can offer is search around for a used/need of repair Shoebox that has good cylinders. Not easy to find, I know, but I believe that there are at least a couple of Forum members here that have been buying old Shoeboxes, so maybe? Possibly start a Wanted To Buy thread in the Classifieds? Sorry not much help on this one.
Good idea, but while OCO Labs does have SOME parts, their CO2 compressors only use the SMALL cylinder, plus they are much shorter, so won't work with a Shoebox. Been there, done that.
Thanks for your comments guys. My F8 has well over 400 hours and only 1 low pressure cylinder rebuild plus a few crank bushings. Love this machine and just looking for insurance lol. May post a classifieds add. Have no idea what I would replace this with. Have no place in my heart for the Chinese stuff