/6 with 4 Speed OD, rear gear recommendations?

I put an A833OD in my 68 Barracuda when it had the \6. The car had 3.23 gears in the 7.25. A couple of years latter I built an 8.25 with 3.55 gears for the car.

There was absolutely no difference in mpg. Before and after the rear swap the car got 19-20 mpg around town and 22-23 mpg on the hiway. BUT, there was a noticeable seat of the pants improvement in acceleration with the 3.55 gears.

With 27" tall tire I am turning 2200 rpm at 70 mph on the hiway.