How about I toss in some REAL times.......

A fast time for an Arabian to run 5/8 of a mile (or 5 FLs) is 1.09

A fast time for a Thoroughbred to run 5/8 of a mile is 0.59

So you do the math, which would be faster. They do hold Arabian races as short as 4 1/2 FL which is just shy of the 5/8 mile.

Also, out in the US the longest distance they hold TB races are 1 1/2 of a mile. The 2 and 3 mile races are steeplechase races that are held in Europe.

Just another FYI, they do hold QH races at a long distance. The longest they hold is 1/2 mile and some of them are darn fast and do spank the TBs at the distance!