3.55 vs 3.73 Gears. Which are best?
I just read through 9 pages of an older thread in the tech section and it sure seems hard to understand people thought patterns on 3.55 vs 3.73 vs 4.10 gears.
At the stoplight torque gets you going. Horsepower - who cares. Torque is what makes a big block a big block and everything else just slower. As they say, there's no substitution for cubic inches. "More cubes" is generally due to a longer stroke. Why do you put a piece of pipe on a wrench to lengthen it to loosen a bolt? Because torque is torque. So if you want a 302 to compete, you put in gears which multiply and increase torque the the rear wheels in an attempt to get the levels available from a big block. Same thing applies to a rice burner. Sure you can throw nitrous in a Civic, but with four cylinders and a short stroke, the torque available means you better have a pretty lightweight car to comptete with. So again torque is torque.
So what gears to pick? In the other forum thread people seemed all concerned about running out of top end power or low gas mileage. The legal speed limit is 65 MPH. How many people are really going faster than say 120 MPH.
A stock 5 speed GT has a 3.35:1 first gear and a .68:1 fifth gear in the T5. With 3.73:1 differential gear you would have a 12.50:1 final drive "launching ratio" and an overdrive "cruise" final drive ratio of only 2.54:1. In other words with 3.73:1 diff gears how could you possibly claim to run out of motor - in OD you're not even hitting 2200 RPMs at 60 MPH! And as for gas mileage, I find it hard to believe 2200 RPM is killing your motor or sucking up that much more gas. Even with 4.10:1 how could you run out of motor?
I'm comparing these numbers to my '66 Mustang with 25" diameter tires, a 4 speed toploader with a 2.78:1 first gear and 1:1 4th gear. With a 3.50:1 rear diff gear, I'm looking at only a 9.73:1 launch ratio and a 3.50:1 final drive ratio. Not as much take off and worse gas mileage. Even with no overdrive the 3.50:1 ratio only put me at 4650 RPM at 100 MPH.
Lower gears only increase the power to the rear wheels so I don't understand how could these people be saying stick with a lower gear like a 3.55:1 because you'll lose power in the top end. That just doesn't make sense. More gear means more power multiplication! That's what makes a gear swap the biggest bang for your buck!
Unless I'm missing something here, I don't see the downside to 3.73 gears!!
The reason I'm asking these questions is that I just bought both a 3.55 and 3.73 gear set today. (Got a really good deal so I bought both figuring I could re-sell the one I don't use.) Can anyone explain to me any reason I would not put the 3.73 gear in!