Only a'32 cab has a firewall that is flat like a'32 car. The '33&'34 fire wall extends out about2-3 inches from the rear hood line. Also a'34 cab has an extra belt line ridge moulding on the back of the cab. Hope that helps you.
Notice the extra wide belt line under the window on this truck cab. Its the distinguishing mark of a 1934
As Bowie said; '32 has a firewall that is basically flush with the cowl. '33 has a firewall that protrudes out from the cowl, and no fat beltline under the rear window. '34 has the fat beltline under the window. I'm sure there are other differences, but those are the easy distinguishing features.
The 32 Truck has a bolt in firewall,all 32's share the same feature. the 33-34 have a welded in firewall and incidentally because of the way it's made allows for a couple of more inches of leg room. As mentioned previously the 32-33 cab is basically the same and share the same body line on the back of the cab. The 34 has the extra wide belt line along with the lines in the previous cabs. It is thought that the extra belt line was to reinforce the cab. HRP
I don't mean to sound like a ****, but do a search. there's a HUGE thread on ID'ing these trucks. the basics are covered here, but there's a fair amount of little stuff here and there too.
The Jalopy Journal
