This turning out to be more difficult that I thought. The clutch and brake linkages have been disconnected, the 4 firewall nuts have been removed, the two top frame bolts have been removed, and the left side retaining bolt has been removed.
The unit is loose, but nowhere ready to be removed. What am I missing? Anyone here undertaken this task?

John

 

You're probably fighting the steering column shaft. It runs right through that area and snags the assembly. Unbolt the steering column from the dash and drop it down a bit. Gives you just enough room to wrestle it out.