Transmission mounted parking brake

[MjrBummer]

Would any of you happen to know a good source to find parking/emergency brake parts for these old trucks? I have a drum on the rear of my transmission attached to the drive-shaft, and a cable dangling there, but that's it. I believe this is the setup I'm looking for in the picture. I think I've heard horror stories of these bursting into flames. Has anybody done any upgrades to a better setup? I always thought my Dad was pretty anal with his work, but after getting a better look at some of the thing he's done over the years to this bus, I'd like to slap him.

Thanks,
Bill