Best gear ratio for windy rural roads street car.

Been having a ton of fun with my car but looking for a little more from the 3.23 gears. Car is a mostly stock 340 , 4 speed. Has an avs2 650 carb , electronic ignition , and is tuned pretty well. At some point I’ll be doing a cam and Intake manifold but would like to get gears sorted first. Tires are 245/60/15. May possibly go up to 255 in the future because I think they will fit my current setup.
I live in Southwest Missouri. Lots of rolling hills and windy roads. I do a lot of cruising around 50 mph and don’t plan on much highway cruising. So a 65 mph cruise speed is good with me. I’m leaning towards 3.73 over 3.91 as they seem like a good compromise without getting too extreme. Would love to hear from some people more experienced than myself. My main goal is building a really fun responsive street car but I doubt the car will ever get built beyond 400hp or so.