Personal Crisis in Western NC: HELP!!!

Ok, here is what I can make of your information:

Desired speed Speedo reading

20 28
25 35
30 42
35 49
40 56
45 63
50 70
55 77
60 84
65 91
70 98
75 105


If your original axle was:

Was V1 (1.4) V2 (1.296) V3 (1.32)

2.76 3.86 3.57 3.64
2.92 4.10 3.78 3.85
3.23 4.52 4.18 4.26

You really need to do the 60 second timing on the highway. The information you supplied has some varaition. 70/54 = 1.296, 93/70 = 1.32 Your speedo says 1.4. There is quite a bit of variation between those three different points of information.

But by running the numbers and seeing which ones make sense, you either went from 2.92 to 4.10 rear axle ratio or 2.76 to 3.57. I think the 2.76 to 3.57 is probably the most possible meaning you went from 2.76 to 3.55 actually. I haven't heard of many (or any) 7 1/4" axles running 4.10 gears from the factory.

So now your new chart is:

Desired speed Speedo reading


20 26
25 32
30 39
35 45
40 52
45 58
50 65
55 71
60 78
65 84
70 91
75 97

However, if you want to impress your friends, tell them your car can do 100 MPH and take them on the highway and get your speedo at 100 and you will be actually doing 77 mph (but don't tell them that). You can get some of them to believe you can actually do 100 with your new axle....

But do the 60 second test on the highway and find out what you are doing when your speedo reads 60 mph consistantly for a mile and then pace up to running 60 seconds between mile markers and record the speedo reading for a mile in 60 seconds. Then we can give more accurate information.

Note* the spacing in the chart got messed up while posting. I typed it right....