Open devmode.lua in the Far Cry directory and add the following code to the bottom:

function GodMode()
if _localplayer then
_localplayer.cnt.health = 99999;
_localplayer.cnt.armor = 99999;
Hud:AddMessage(''[CHEAT]: Give 99999 health and armor'');
System.LogToConsole(''\001CHEAT: Give 99999 health and armor'');
else
Hud:AddMessage(''[CHEAT]: No godmode today'');
end
end

Then, start the game with the -devmode switch and open the console with the ` key. Type in: #GodMode() and you'll have 99999 health and armor. The normal maximum is 255.

Saving or loading a game will reset the values, though.