I was too young for the Oxford match but by all accounts it was probably the last time there was a crowd above 40,000 in Ayresome (unofficially of course) although it was sometimes rammed in the 1970’s and the crowd was ‘declared’ at the official safe capacity.
The Liverpool semi final was a superb atmosphere and there have been plenty of others at the Riverside when it has been throbbing, and not necessarily just for really big matches either.
I think the enclosed roof at the Riverside helps the volume, Ayresome was a bit wide open to keep the sound in but the packed terraces generated a different kind of intensity. I also think our fans generally were more biased and partisan in those days, none of this modern ‘let’s be honest with ourselves’ nonsense you get these days, it was red and white glasses as standard issue.