bgrd,

I ran a '63 Nova with a fairly mild 400 small block, 3500 stall powerglide and 5.13-1 gears. At 1400 ft elevation those gears were just right. When I came down to sea level I ran out of RPM about 150 before the finish line. I had planned to drop to 4.88-1 gears, but sold the car before I got around to it. This was on a track only car. I was running 10.5 x 28.5 tires. That is as tall as I could get under the car. My wheel wells were radiused to get the tires in there.

Other considerations are tire diameter, the RPM range where your motor makes it's power, timing, weight of the car, how well it's hooking up and on and on. I agree the best thing to do is get some time slips, including 60 foot times and start experimenting from there. Remebmer that shorter tires also act like a lower gear.

Keep us posted on your project and good luck

Pat