93 Games Studio never released an "official" conversion guide. However...
Most small arms should be easy for players to map, using the existing weapon stats (and the master ammo table from the link in my sig file).
(Edited to add: Previous discussion on this topic
here.)
If there's a need for a small number of heavy weapons conversions, I can try to dig up the equations we originally used for those.
There's no good way to directly convert characters, as the life path systems are not designed to be compatible. My suggestion would be to rework the character from the ground up, using the original concept and following the closest equivalent life paths in the 2013 book.
Vehicles are sort of complex because the armor values need to align with the actual performance of the weapons they're designed to defeat, so there's no direct formula for converting armor thickness and material to armor values. Speed and fuel consumption were based directly on converting real-world traits to game traits. Most other traits were qualitative rather than quantitative. Again, if there's a need for a small number of conversions, feel free to ask.
- C.