Peter Birmingham
Well Known Member
My friend has a 63 Impala with a 409 and a four speed transmission, the rear end gear ratio is 4.10:1. It seems when he runs at highway speed, 60 - 70 the car really has a humming to it. He wants to use the car as a cruiser but still have a little snot off the line. Would changing the rear end gear ratio to 3.70:1 or 3.50:1 make it run smoother? How about a 3.20:1 ratio? I really don't understand the ratios, that well, looking for some help.