What Transmission?

[osaltyone]

This truck was passed down to my wife and after a year of it sitting in the garage I decided to start tackling some of the issues. Truck was "restored" to use in parades waaay back in the day, but looks like they used lots of tar and rivets to cover the rust holes and nothing was done to the underside.
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Started with a disc brake conversion and as I read the instructions it said I need a tubular trans mount. I climbed under to take a look at the current one and noticed the rear transmission mount is missing and something is being held in place by bailing wire. What transmission would be installed on this truck? It has 3 on the tree and a 216 in it that runs, but hasn't been driven in over 20yrs, so I'll leave it for now.