I don't know if any of them would fail. The biggest EMP problem, in theory, is for devices with integrated circuits that are hooked to things that act like antennas and absorb the pulse. That can be the electric grid, actual antennas, etc.
Little recent "real world" testing has been done since above ground nuclear testing has been banned since the early 60s.
Regardless - I assume any tractor that lacks ICs to run is absolutely safe. Gas engine with ignition points and coil, diesel with mechanical injection, etc. The only parts of some of those tractors that may have an IC or two are the charging systems IF they have alternators with ICs in the regulators.