What type of rear do you have? Stock? I'd stick with a 3:55 ratio. It's a good all around ratio that will give you great low end torque and good cruizin' gears.
I have a 3:55 with my 292 and T-5 that has a 0.72 OD. I get 1850 RPM's at 65mph with 31" tall rear tires. Good gas mileage too with 18 mpg with 3-HW's.
RapRap
1940 ChoppedChevyCoupe
