The factory gear ratio is 4.44:1, but I know what you are saying. To switch to something like a 4.0:1 or even a 3.9 might help with traction somewhat under boost. Long ago I had a Nova that picked up 1.3 seconds in the 1/4 mile with nothing more than a switch from a Turbo 350 trans to a powerglide with a 10" converter. I got more traction out of the hole with a launch rpm around 4K. That car launched pretty hard and still had wheelspin to 40 mph. I never got around to using slicks as the drivetrain was splitting the car in two.

Charles