Originally Posted by asleep.at.the.oars
That looks like someone retrofit a Halkey-Roberts into the boot of a military valve. Done right (or at least how I think would be right), you would cut out the entire boot, do an inside & outside patch with the new valve base on the inside and then screw in a new A7. Pretty big job if you've never patched before, but no baffles or crazy stuff so still doable with some patience. You might be able to take out the current valve and see if you can get some new pieces to fit as well.
Edit: I initially said no crazy stuff, then I noticed the wear strip overlaps the boot fabric. That's actually kind of complicated unless you want to sacrifice some wear strip which is hard with the way Maravia paints on the Class VI (urethane or whatever it is) coating. Not sure if anyone good is closer, but Herm Hoops up in Vernal could do it.
If you cut out the boot, you want to replace it with a c7, not an a7. I agree thought, the proper fix would likely be a c7 conversion. I could do it, but I don't have much time right now. To do it proper I would want an inside patch and an out side patch covered with color matched urethane. It is pretty involved and would cost some money. One of the raft repair places in Salida wouldn't be to far for you to drive, but let me know if you want some semi-professional help in Montrose.
Im not sure which kind of valve that is, but I think it is a liefield. If you can find parts it may be cheaper in the short term.