"HEY GRUMPYVETTE?
I have a Hurst Olds 3.73 rear gear, with a factory manual trans. clutch linkage. What would be the best first gear (say a 3.27 or a 2.87) in a 5-speed overdrive trans. The truck won't see the track, but will see some highway (could see a 100+ mile from time to time) trips. I'm guessing about a 275/60/15 tire.
Two transmissions I'm looking at have gears of:
3.27, 1.97, 1.34, 1.00, and 0.68
2.87, 1.89, 1.28, 1.00, and 0.64
With the 3.73 rear gears, I'm leaning toward the 2.87 first gear.
Thanks!"
http://www.jekylhyderacing.com/HeightofTires.htm
http://vexer.com/automotive-tools/speed-rpm-calculator
most experienced engine builders and transmission shops will tell you that you should always try to get the first gear ratio multiplied by the rear gear ratio to fall in the 10:1-10.5:1 range with tires shorter than about 27" and between 10.5:1-11:1 ratio with tires taller than about 27"
your 275/60/15 tires are about 27.7" tall
3.27 x 3.73=12.2:1 (not going to work well)
2.87 x 3.73=10.7:1 (much closer to ideal)
I have a Hurst Olds 3.73 rear gear, with a factory manual trans. clutch linkage. What would be the best first gear (say a 3.27 or a 2.87) in a 5-speed overdrive trans. The truck won't see the track, but will see some highway (could see a 100+ mile from time to time) trips. I'm guessing about a 275/60/15 tire.
Two transmissions I'm looking at have gears of:
3.27, 1.97, 1.34, 1.00, and 0.68
2.87, 1.89, 1.28, 1.00, and 0.64
With the 3.73 rear gears, I'm leaning toward the 2.87 first gear.
Thanks!"
http://www.jekylhyderacing.com/HeightofTires.htm
http://vexer.com/automotive-tools/speed-rpm-calculator
most experienced engine builders and transmission shops will tell you that you should always try to get the first gear ratio multiplied by the rear gear ratio to fall in the 10:1-10.5:1 range with tires shorter than about 27" and between 10.5:1-11:1 ratio with tires taller than about 27"
your 275/60/15 tires are about 27.7" tall
3.27 x 3.73=12.2:1 (not going to work well)
2.87 x 3.73=10.7:1 (much closer to ideal)