https://youtu.be/ACbyIrMvr7s?t=881
This is the same setup I'm putting in my Cobra. Wondering about rear gears. I should be 350-400 pounds lighter and also a 125hp shot of NOS! The Mazda has 3.42 gears with 23.6" tires. My current 4.11 with 27.8 tires is within 2 mph through 5th gear. The gears on the Miata hit almost perfect, 100 mph @ redline in 3rd for the 1/8th and 130 mph in 4th at redline for the 1/4. I hope to better the Miata even without the NOS, but I don't want to add a shift! I'm thinking 3.73 maybe 3.55?
4.11 = 101 mph in 3rd and 132 in 4th (6500 rpm)
3.73 = 111 mph in 3rd and 144 in 4th
3.55 = 116 mph in 3rd and 151 in 4th