really, all you need is a start up tune for 120's
if its a gas tune just load the tune go to your system config, then fuel calc parameters and adjust the fuel energy constant from 1 (gasoline) to 0.680 (e-85)
also that is where you can adjust the injector size
other tables will have to be adjusted like cranking fuel some of the ae tables under the fuel tables section ect ect im sure others will chime in as well...
-dan