No, I have not done a actual top 50 ranking list.
But he was in the all-time top 10 in the 3000m until 1984, in the 2 Miles (in and out) until 2000, in the 5000m until 1982 and in the 10000m until 1978. Puttemans has faster PBs than Viren in any event from 1500m to 5000m (1 second slower in the 10000m) and also an world class steeple. Behind Henry Rono, he definitely was the best long distance runner against the clock of the 1970s. For me that's enough to guarantee him a place in the top 50.
And if there are 70 people who can make the same arguments, how can they all be top 50?
Impossible that there are 70 runners who can make those arguments. Name just 30.