I like doing it yards per game to declutter from from the more games argument.
NFL Single-Season Passing Yards per Game Leaders Through 1990 | Pro-Football-Reference.com
Through 1990, only three pre-1978 names made the top 40.
It’s basically the same as today, but some how the ‘78 rule changes for WR contact and olinemen extending their arms were not a big deal.
And you can argue that this had a bigger impact than the WR contact rules.
That’s another thing, how many average offensive lineman from the 50’s and 60’s would dominate if you put them post 1978 with those rules for pass blocking. It was so much harder back in their era