Ballpark Gear Ratio

I used to run a very similar combo on a 71 Duster 340 I had in the early 90's, 340 .040 over, ported T/A heads with Manley SS valves, 292 purple shaft cam, M1 single plane intake, 750 Barry Grant Carb (I think those flowed like 900/950 CFM), 10.5:1 compression, 1 3/4" headers, 727 with a 3500 Turbo Action converter, reverse valve body. Complete car with full bucket seat interior and console, non-A/C car, with PS and PB. I ran 4.30 gears but at the track I used a 28x9 slicks. Only took it twice to the drag strip, but the second time it ran 12.6 at 116 MPH. With a 26" tire I would say 4.10 is probably your best bet. This was a street car and it was a pain to run it with 4.30 gears on the street and the loose converter.