I've copied (below) the additional scenes listed on IMDb that were supposedly in the FULL length version, that were not included in the 227 minute U.S. version:

....................... SPOILER MATERIAL LISTED HERE .....................

Italian original version of the film is 236 minutes long. The US distributor cut over an hour and a half for the 139 minutes American version; after much critical protest, the film was shown on network TV in a 192 minutes cut and finally was made available in an almost complete 227 version on video (which reportedly still omits segments from the scene where Robert De Niro rapes Elizabeth McGovern).

According to an interview given by Sergio Leone's son in november 1998, Regency and Warner are planning to reconstruct and re-release Sergio Leone's original 250-minutes director's cut and have requested the missing footage from him. Among the missing sequences that may be restored to the film are:

Noodles as a kid comes back home after the failed attempt to steal the drunk's clock and finds that his father has eaten all his dinner;

Noodles and Max rob a black trumpet player and steal his wallet and trumpet;

Old Noodles (De Niro) notices a black car following him after he leaves Riversdale Cemetetery, and he takes notes of the license plate. The same black car is later seen blowing up in front of senator Bailey's house

Noodles gets drunk after his failed attempt to rape Deborah; he picks up a hooker but falls asleep in the bed instead of having sex with her;

An old Jimmy O'Donnel (Treat Williams) meets senator Bailey and convinces him that suicide is his only way out.

British versions have been censored to remove the scene where a gun is pressed into a breast.

The Japanese Laserdisc contains 2 extended scenes cut from all U.S. theatrical & video prints:

Opening murder contains extra shots of Darlanne Fleugel suffering and being shot a second time before dying.

DeNiro's rape of Elizabeth Mcgovern is much longer and more graphic.

The so called director's cut does not exist in a finished state. Nino Baragli never edited the extra scenes and the cast didn't sound loop their dialogue to those extra scenes.

The 2 cuts made by the BBFC in the UK (a gun being pressed to a woman's breast and De Niro tearing off Elizabeth McGovern's underwear in the rape scene) were reinstated in the (now deleted) widescreen version.

There is a picture/still from 'Once Upon a Time in America' which is often in books/chapters on the film. The picture is of Noodles (De Niro) and Eve in bed together, and Noodles is getting out of bed holding a gun as he's clearly heard someone coming in. This scene is definatley not in the 227 min version.

I have not heard of any expected DVD release of the movie.