Anybody running 276 gears?

And second gear, too.

Original Torqueflite ratios, first-second-third gears:
2:45, 1.45, 1.00

Wide-ratio Torqueflite ratios, first-second-third gears:
2.74, 1.54, 1.00

I put together a '65 with a healthy 225, 2.76 rear gears, and a wide-ratio gearset in the A904. I figured that would be a great combination. It wasn't; I hated it for a bunch of reasons, and from that I learned that the wide-ratio gearset, without an overdrive 4th gear, seems (to me) best suited for the vehicle configurations it was designed for: a weak engine and a tall rear axle in a heavy vehicle. Add an overdrive 4th gear (A500, A518…) and choose the rear axle in accord with that, and the picture changes.

When I went back to standard ratios in the trans and 2.94 or 3.23 rear gears in my '65, I wound up much happier. That is only one data point, however; others' experiences will differ with different engines and cars.
I have to say I'm surprised to read that. I've not found a combination yet that doesn't improve with a lower first transmission gear. I hoard the early six-banger A833 3.09-first gearsets for just that reason.