01-26-2017, 08:19 AM
The present rear ratio is to low. The Cummins turns up more than the Detroit. I am seeking a set of 3:55s for the change, but must determine what rear I have. There are no tags left on the axle to help me. Assume it to be a Rockwell SQ but don't want to get wrong ring and pinion set. Was hoping to find someone with a 79 who might be able to read the tag on the rear axle. Thanks for the help. With the current rear it will not reach 50 MPH at 2000 rpm so obviously this will not due.