As many of you, I second guessed this mod forever. I was so paranoid about higher revs on the highway, etc. I recorded all rpm at different speeds with the 3.55's (manual). Basically, 70, 75, 80. I haven't written them all down with the 4.10's but at 70 I was up 300 rpm. The car responds so much better that it's hard to kill this mod over that. Anyway I'll post the increases by rpm later. If you're on the fence, just do it. I thought the guys talking about 4.30's were nuts, but now....

 

I second that, 4.10s FTMFW!!!!

 

You dont need to post any numbers, its been done before: https://mustangforums.com/forum/4-6l-v8-technical-discussions/446207-gears-wheels-tires-revs-rpms-and-mphs.html

- OR -

Use the calculators, its pure mathmatical equations: http://www.wallaceracing.com/Calculators.htm

 

Glad you like 'em. I have an auto, so I'm going with 3.73..install is next w/e.
This is from the gear calculator spreadsheet.

4.10 manual with 255/45 18 27" tire diameter

----------------MPH--------------
RPMs ---1----2----3-----4----5--
1900 11.03 18.64 28.24 37.27 55.22
2000 11.61 19.62 29.72 39.23 58.12
2100 12.19 20.60 31.21 41.20 61.03
2200 12.77 21.58 32.70 43.16 63.94
2300 13.35 22.56 34.18 45.12 66.84
2400 13.93 23.54 35.67 47.08 69.75
2500 14.51 24.52 37.15 49.04 72.66
2600 15.09 25.50 38.64 51.00 75.56
2700 15.67 26.48 40.13 52.97 78.47
2800 16.25 27.46 41.61 54.93 81.37
2900 16.83 28.44 43.10 56.89 84.28
3000 17.41 29.43 44.58 58.85 87.19
3100 17.99 30.41 46.07 60.81 90.09
3200 18.57 31.39 47.56 62.77 93.00
3300 19.15 32.37 49.04 64.74 95.91
3400 19.73 33.35 50.53 66.70 98.81
3500 20.31 34.33 52.02 68.66 101.72

3.73 Auto 255/45 18 27" tire

----------------MPH--------------
RPMs ---1----2----3-----4----5--
1900 12.72 17.89 26.60 40.97 57.70
2000 13.39 18.83 28.00 43.13 60.74
2100 14.06 19.77 29.40 45.28 63.78
2200 14.73 20.72 30.80 47.44 66.82
2300 15.40 21.66 32.20 49.60 69.85
2400 16.07 22.60 33.60 51.75 72.89
2500 16.74 23.54 35.01 53.91 75.93
2600 17.41 24.48 36.41 56.06 78.96
2700 18.08 25.42 37.81 58.22 82.00
2800 18.75 26.37 39.21 60.38 85.04
2900 19.42 27.31 40.61 62.53 88.07
3000 20.09 28.25 42.01 64.69 91.11
3100 20.76 29.19 43.41 66.85 94.15
3200 21.43 30.13 44.81 69.00 97.19
3300 22.10 31.07 46.21 71.16 100.22
3400 22.77 32.02 47.61 73.31 103.26
3500 23.44 32.96 49.01 75.47 106.30

 

yeah im thinking maybe 4.30 or 4.56?????
Ideas