I get that running 12 flat 1/8ths for a mile and half is Secretariat. But to be clear, I said 12 and change 1/8ths, not 12 second flat 1/8ths. And there's a big difference between those two statements. Run the numbers and see what times you come up with.

On the upper end, at 12.8 1/8ths you would have 6F in about 1:16. That's crawling.

In the middle at 12.5 you would wind up with fractions that look like this: 25, 50, 1:15, 1:40, 2:05, 2:30. That's still pretty slow early.

On the lower end, at 12.2 you get 24.4, 48.8, 1:13.2, 1:37.6, 2:02, 2:26.4 which would be a pretty strong race.

Of course horses don't usually run evenly every 1/8th. But even if you take the 12.2 numbers above, if a front runner set those types of fractions early and gradually slowed down a few ticks for the last few, which is more representative of what actually happens, you would have a race that finished in 2:28 and change.

The front runners are able to hang around at those kinds of splits, at least for a piece of it.