This section is for features only.
When super 8mm was at its peak from the mid 70's to the very early 80's, most of the feature releases in the UK were issued to a standard length, usually 8 reels (4x400ft). Films that were released in colour were nearly all in his format, due to the cost. Some of the Black & White titles were released full length though, especially the 'Classics'.
Mountain Films released "King Kong" on 12 reels plus a few others "Top Hat" was one I believe. Walton Films did the same for "The Third Man" and "Reach For The Sky". Powell Films were also to release titles complete. DCR Films I think all their films were complete, as were Movieland's. Derann also had a few complete films at this time. They were later to release almost all their titles complete.
Standard 8mm titles from looking at the old advertisements a large amount were released complete. And of course in 16mm were all complete, but for hire only. A few cut-downs were sold in the UK from the likes of Castle Films.
Blackhawk, Thunderbird Film and others when you look at the old catalogues had a lot of titles in both 8mm gaughes and 16mm.
Releases from America were on a whole complete.