Statistics show that Gibson did, in fact, hit 84 home runs during the 1936 season. However, it is important to realize that only a percentage of these homers came in games against top Negro League competition.
The official league season for most Negro League teams was limited to 40 to 60 games during most years. The remainder of the games a Negro League team would play (up to an additional 150 games) were games against much weaker competition, including semi-professional teams.
There is no question that Josh Gibson was a prodigious hitter and one of baseball’s best all-time homerun sluggers, but the nature of the Negro League season and the quality of existing statistics do not allow for direct comparison to the established records of major league baseball.