Just to add some further info on the two English dubs: the longer cut (or ‘International Version’) (113min PAL) was first passed uncut by the BBFC for release in 1968. Whether this version was ever shown theatrically in the UK is unknown; but it was released on VHS (in widescreen) in 1993, with Alex Cox’s ‘Moviedrome’ introduction from 1990 printed in full on the back. The only version specific to the UK is a heavily truncated 77mins theatrical cut rated X (c.1969).
The other English dub was produced at some unspecified date and prepared solely for the US market.
William Berger who dubs El Niño (although a great voice) sounds too old for the role and the actress who dubs Adelita is better in the other version - although both inferior to Rita Savagnone in the Italian dub. However the voice acting is not the primary reason to avoid this version.
This version also has a different and equally unnecessary voice-over; it also cuts the magnificent opening at Baza station. Damiano Damiani’s cameo is cut completely. This scene is longer in the original Italian theatrical version and accounts for the 3min disparity in runtime with the ‘International Version’. But probably the most significant change is to the dialogue during the finale where ¿quién sabe? is not only translated into English - but also incorrectly.