I made a chart with the gear ratios in my SM420 along with the rear end so I could see final ratios. Both my 55.2 and 58 2-tons are the same, anyway, you would shift as follows:
1lo, 1 hi, 2 low, 2 hi, etc.... you may or may not need to use lo and hi, if you have enough engine and are not loaded and on the flat, you might get by leaving the rear in hi and just shifting the tranny. Final ratios are below, in order (1 lo, 1 hi, 2 lo, 2 hi, etc) my chart will not stay formatted when I paste it.
61.775, 45.184, 31.325, 22.912, 14.9625, 10.944, 8.75, 6.4
