other than the cases and a better crank
i looked at the 120 last yr, it was being sold as an upgrade kit for 96ci motors, it was pistons, barrels, cams, clutch the whole nine yards, but what it did not include were - timken bearings, proper cam bearings, a few other bits that would be needed with a power plant like this - specially if you wanna ride it all day everyday.
It could also be bought with cases ready to go but they came in black only.
If you have already had the motor bored to take a 110+ motor you cannot use the 120 without new cases, if you have a factory 110 you cant have the 120 with out new cases
if your looking at big capacity motors then look further afield at compaines like S&S, Rev tech, Kendle Johnson, RB racing who have been doing BIG BORE for years before HD jumped on the band wagon