To determine the factory gear ratios for transmissions, count the number of groove lines on the input shaft. Here are some common transmisions with gear charts

Muncie 4 speed

                   1st                 2nd             3rd               4th

No lines     2.56             1.91              1.48             1.00

1 line        2.20              1.64              1.28             1.00

2 lines     2.52                1.88              1.46            1.00

Super T-10

                1st                  2nd                3rd                  4th

2 lines     2.43                1.61                1.23               1.00

3 lines    2.64                 1.75                1.33               1.00

5 lines    3.42                 2.28               1.46                1.00

6 lines    2.88                1.91                1.33                 1.00

Saginaw 3 speed

                      1st                  2nd                    3rd               

No lines       2.85                 1.68                   1.00

1 line            2.54                 1.50                   1.00

2 lines           3.11                 1.84                  1.00

3 lines           3.50                 1.89                  1.00

Saginaw 4 speed

                          1st                   2nd               3rd                4th

No lines             2.84                2.01               1.35             1.00

1 line                 2.54                1.80                1.44             1.00

2 lines               3.11                2.20                1.47              1.00

3 lines              3.50                2.47                 1.65              1.00