I have a 1949 Plymouth Business Coupe, as well as a 1954 Chrysler Windsor Deluxe. Regarding the Chrysler, I pulled the pinion with the part no. 1325696 16T. I was not able to locate the same part, but was able to obtain part no. 652 848 17T. My tire size is 7.60 x 15, but I don't know my ratio . I would think that I could use the part I was able to obtain, but that my speedometer would be a little off that I could check with a GPS Speedometer. Would I by doing any harm with this change, which is also from nylon to steel?