5 inch height difference
remember jordan was measured barefoot 6 4
lebron is 6 9
Nope, it was Jordan, and he did it with legit centers and hand checking, long read but interesting if you are a fan.
Comparing Jordan's Dunking Data to Contemporaries
For the 6 seasons between 1988 and 1993, Jordan had 746 dunks, or an average of 125 dunks per season.. His high was 158 (1988), and his low was 95 (1993)... (links to complete dunk data for each season are at the bottom of this post)
By comparison, from 2002-2009 (Kobe's athletic prime and highest volume period), Kobe averaged 65 dunks... Tracy McGrady averaged 75 dunks from 2001 to 2005 (his athletic prime and highest volume period)... Vince Carter in his prime and Paul George only get about 50 dunks per season.
Infact, Jordan's dunk totals dwarf every single wing player from this era except Wade, Lebron, and Durant... These are the only players that routinely amass over 100 dunks per year, although none of them have as many dunks over a 6-year period as Jordan - the high for any of these three players is 144, by Lebron this year.... Jordan has a season of 153 dunks and another with 158 dunks, and we don't have data for his biggest dunking year - 1987 when he averaged 37.1ppg on 27 shot attempts (still had 59%TS).
Looking at the Dunking Environment Across Eras
Of course, different eras use different rules and styles of play which affect how easy it is to get a dunk - this will sound crazy, but Lebron dunked over defenders in a chest-to-chest scenario only 3 times the entire 2014 season - every other time the spacing and defensive 3 seconds prevented defenders from getting to the spot in time... and most of Lebron's dunks were completely wide open, not even a reach-in or fly-by - the 3-point shooting and floor-spacing creates too much ground and extra space for the defense to cover.... confirm for yourself... here are every single one of Lebron's dunks for the 2014 season - only 3 posters.
All Lebron dunks from 1st half of season... https://www.youtube.com/watch?v=jCYKuK84cCQ
All Lebron dunks from 2nd half of season... https://www.youtube.com/watch?v=BiApca7OtE0
After you've watched Lebron's dunks in the 2014 season, compare that to Jordan's dunks in 1987... https://www.youtube.com/watch?v=SQH7_BW9hCI&t=2m12s
RIGHT AWAY you can tell that there's a massive difference - there is no spacing and less room between defenders because the defense is packed-in so they can better defend only 2-pointers, and shot-blocking big men are camped in the paint awaiting penetrators (rather than today's game where helping on penetration involves scrambling from the three-point line to the paint and then making sure you aren't in there for more than 3 seconds).
The lack of spacing meant Jordan had to frequently dunk over and through guys if he wanted to dunk - so much so, that even with the limited footage available from back then, it is easy to find literally hundreds of Jordan dunks over defenders... For example, listed below are links to various collections of Jordan posters (very partial collections)... you could never accumulate collections like this for Lebron, because today's game with the spacing doesn't allow this level of shot contestion, so Lebron doesn't even have a small fraction as many posters as Jordan has.