GM/CHEVROLET FINAL DRIVE RATIOS
It is the gear under your seat that counts. Gearing is what you are
buying when you purchase a Gear Vendors Under/Overdrive. If you take a few moments to
study the gear chart for your transmission and rear end ratio combination you will see why
this product is so popular. The Final Drive Ratio shows you how many times the engine
turns for one complete turn of the tires. Gears are multiplier of torque. The mathematical
equation for Horsepower is; Torque X RPM/5252 = HP. Close ratio gearing lets us work both
the torque and rpm side of this equation for big gains in HP and performance. Notice for
instance that 1st-over has a lot more torque multiplication than 2nd - now look how low
you would have to go in rear end ratio to make your second gear have as much torque as
1st-over. Same with 2nd-over compared to 3rd.
Whatever your 2nd-over final drive number is - that is equivalent to
having that ratio for a rear end torque multiplier. Of course, with gear-splitting we
are keeping the engine rpm up from one shift to the next and further exploiting the
ratio benefit.
There is not room here to cover all the details (like the benefit
to passing gear and such) so call us at the factory to discuss your exact application
- we have customer service guys on hand for you to ask these types of questions.
| TH350 3-SPEED AUTOMATIC |
| |
Axle Ratio |
4.56 |
4.10 |
3.73 |
3.55 |
3.42 |
3.08 |
| |
Trans Ratio |
Final Drive Ratio |
| 1st |
2.52 |
11.49 |
10.33 |
9.40 |
8.95 |
8.62 |
7.76 |
| Over |
1.97 |
8.96 |
8.06 |
7.33 |
6.98 |
6.72 |
6.05 |
| 2nd |
1.52 |
6.93 |
6.23 |
5.67 |
5.40 |
5.20 |
4.68 |
| Over |
1.19 |
5.41 |
4.86 |
4.42 |
4.20 |
4.06 |
3.65 |
| 3rd |
1.00 |
4.56 |
4.10 |
3.73 |
3.55 |
3.42 |
3.08 |
| Over |
0.78 |
3.56 |
3.20 |
2.91 |
2.77 |
2.67 |
2.40 |
| TH375/400/475 3-SPEED AUTOMATIC |
| |
Axle Ratio |
4.88 |
4.56 |
4.10 |
3.73 |
3.55 |
3.42 |
| |
Trans Ratio |
Final Drive Ratio |
| 1st |
2.48 |
12.10 |
11.31 |
10.17 |
9.25 |
8.80 |
8.48 |
| Over |
1.93 |
9.44 |
8.82 |
7.93 |
7.22 |
6.85 |
6.60 |
| 2nd |
1.48 |
7.22 |
6.75 |
6.07 |
5.52 |
5.25 |
5.06 |
| Over |
1.15 |
5.63 |
5.27 |
4.73 |
4.31 |
4.09 |
3.95 |
| 3rd |
1.00 |
4.88 |
4.56 |
4.10 |
3.73 |
3.55 |
3.42 |
| Over |
0.78 |
3.81 |
3.56 |
3.20 |
2.91 |
2.77 |
2.67 |
| 700R4/4L60E 4-SPEED AUTOMATIC OVERDRIVE |
| |
Axle Ratio |
4.88 |
4.56 |
4.10 |
3.73 |
3.42 |
3.23 |
| |
Trans Ratio |
Final Drive Ratio |
| 1st |
3.06 |
14.93 |
13.95 |
12.55 |
11.41 |
10.47 |
9.88 |
| Over |
2.39 |
11.64 |
10.88 |
9.79 |
8.90 |
8.17 |
7.71 |
| 2nd |
1.63 |
7.95 |
7.43 |
6.68 |
6.08 |
5.57 |
5.26 |
| Over |
1.27 |
6.20 |
5.80 |
5.21 |
4.74 |
4.34 |
4.10 |
| 3rd |
1.00 |
4.88 |
4.56 |
4.10 |
3.73 |
3.42 |
3.23 |
| Over |
0.78 |
3.81 |
3.56 |
3.20 |
2.91 |
2.67 |
2.52 |
| 4th GM O/D |
0.70 |
3.42 |
3.19 |
2.87 |
2.61 |
2.39 |
2.26 |
| Double OD |
0.55 |
2.67 |
2.49 |
2.24 |
2.04 |
1.86 |
1.76 |
| 4L80E 4-SPEED AUTOMATIC OVERDRIVE |
| |
Axle Ratio |
5.13 |
4.88 |
4.63 |
4.56 |
4.10 |
3.73 |
3.42 |
| |
Trans Ratio |
Final Drive Ratio |
| 1st |
2.48 |
12.72 |
12.10 |
11.48 |
11.31 |
10.17 |
9.25 |
8.48 |
| Over |
1.93 |
9.92 |
9.44 |
8.95 |
8.82 |
7.93 |
7.22 |
6.60 |
| 2nd |
1.48 |
7.59 |
7.22 |
6.85 |
6.75 |
6.07 |
5.52 |
5.06 |
| Over |
1.15 |
5.92 |
5.63 |
5.34 |
5.27 |
4.73 |
4.31 |
3.95 |
| 3rd |
1.00 |
5.13 |
4.88 |
4.63 |
4.56 |
4.10 |
3.73 |
3.42 |
| Over |
0.78 |
4.00 |
3.81 |
3.61 |
3.56 |
3.20 |
2.91 |
2.67 |
| 4th GM O/D |
0.75 |
3.85 |
3.66 |
3.47 |
3.42 |
3.08 |
2.80 |
2.57 |
| Double OD |
0.59 |
3.00 |
2.85 |
2.71 |
2.67 |
2.40 |
2.18 |
2.00 |
| M465 4-SPEED MANUAL |
| |
Axle Ratio |
4.56 |
4.10 |
3.73 |
3.42 |
| |
Trans Ratio |
Final Drive Ratio |
| 1st |
6.55 |
28.91 |
26.86 |
24.43 |
22.40 |
| 2nd |
3.58 |
16.32 |
14.68 |
13.35 |
12.24 |
| Over |
2.79 |
12.73 |
11.45 |
10.41 |
9.55 |
| 3rd |
1.70 |
7.75 |
6.97 |
6.34 |
5.81 |
| Over |
1.33 |
6.05 |
5.44 |
4.95 |
4.53 |
| 4th |
1.00 |
4.56 |
4.10 |
3.73 |
3.42 |
| Over |
0.78 |
3.56 |
3.20 |
2.77 |
2.67 |
| GM NV4500 5-SPEED MANUAL |
| |
|
Axle Ratio |
| |
|
4.56 |
4.10 |
3.90 |
3.73 |
3.55 |
| |
Trans Ratio |
Final Drive Ratio |
| 1st |
5.61 |
25.58 |
23.00 |
21.88 |
20.92 |
19.92 |
| 2nd |
3.04 |
13.86 |
12.46 |
11.86 |
11.34 |
10.79 |
| Over |
2.37 |
10.81 |
9.72 |
9.25 |
8.84 |
8.42 |
| 3rd |
1.67 |
7.62 |
6.85 |
6.51 |
6.23 |
5.93 |
| Over |
1.30 |
5.94 |
5.34 |
5.08 |
4.85 |
4.63 |
| 4th |
1.00 |
4.56 |
4.10 |
3.90 |
3.73 |
3.55 |
| Over |
0.78 |
3.56 |
3.20 |
3.04 |
2.91 |
2.77 |
| 5th Dodge O/D |
0.74 |
3.37 |
3.03 |
2.89 |
2.76 |
2.63 |
| Double Over |
0.58 |
2.63 |
2.37 |
2.26 |
2.16 |
2.06 |
| M21/22 4-SPEED Close Ratio - showing clutchless options |
| |
Axle Ratio |
4.88 |
4.56 |
4.10 |
3.73 |
3.55 |
3.42 |
| |
Trans Ratio |
Final Drive Ratio |
| 1st |
2.20 |
10.74 |
10.03 |
9.02 |
8.21 |
7.81 |
7.52 |
| Over |
1.71 |
8.35 |
7.81 |
7.02 |
6.38 |
6.08 |
5.85 |
| 2nd |
1.64 |
8.01 |
7.48 |
6.72 |
6.12 |
5.82 |
5.61 |
| Over |
1.28 |
6.23 |
5.82 |
5.23 |
4.76 |
4.53 |
4.36 |
| 3rd |
1.28 |
6.25 |
5.84 |
5.25 |
4.77 |
4.54 |
4.38 |
| Over |
0.99 |
4.86 |
4.54 |
4.08 |
3.71 |
3.54 |
3.41 |
| 4th |
1.00 |
4.88 |
4.56 |
4.11 |
3.73 |
3.55 |
3.42 |
| Over |
0.78 |
3.79 |
3.55 |
3.19 |
2.91 |
2.77 |
2.66 |
GEAR VENDORS, INC. 1717 North Magnolia Avenue, El Cajon, CA 92020
Toll Free 800-999-9555 • Telephone (619) 562-0060 • Fax (619) 562-1186
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