Bob Foster ranked No.23 by ring magazine in a list of the best fighters in the last 50 years

Info from 1996:
Record: 56-8-1 (46)
Quality of competition: 9
Bouts vs Top 50 fighters: 3
Why he`s here: At his weight, he was virtually unbeatable
What he could have done to better his ranking: Beaten at least one or two of those big name heavyweights.
Where would you have have ranked Foster if he had beaten a Top Ten heavyweight during his era and could any other light heavy in history have done better than Foster did at heavyweight against the opponents he fought in that era?