a better comparison would be if you could beat Bekele's 1,500m and 3,000m times (like Dave beat Al's 24hr, 48 and 72 hr times) and then attempt to beat his 10,000m time you may think you have a chance
I think that all of Al's 48 and 72 hour performance were splits. In the 90ies there was only one 48 hour race in France and 72 hours was non existing. 6 day performances you have to measure against and that is won by Al easily with 226 km more than Dave's performance.
Most important are Al's performances at the SCMT multiday races over 1300 miles. Al was the first to actually finishing it.
Al Howie's Trans Canada performance is one of the all time best performances in multiday running in my opinion. Just because it was done in 1991 does not mean that anyone can beat this easily today.