I can tell you the 7R8T means a 158" wheelbase for a F-4/5/6 truck.
It should have a Canadian vin number on the left side frame rail in the engine compartment and under the cab just after the transmission crossmember on the same side. I assume its also missing the tag plate on the top center of the firewall in the engine compartment.
There should also be a plate beside the starter solenoid on the right hand on the firewall. Can't quite remember what is exactly on this one but might help narrow it down.
You may have an Effie but I have a Emmie! TM
'51 Mercury M-3 Extra 5 Star Cab Dually "Faith"
5.4L, AOD, Dana 70 3.73:1, Twin-I-Beam
Built to play and work hard!