GPS speedo app on phone make it easy to dial in a mechanical speedo. Drive 50 mph & see where the speedometer reads. difference either = or - , times 2 will give the % either plus or minus. With that info either do the math on drive / driven gear or get a speedo adapter. Some of us have several different ratios adapter rat holed, post what you need and might get a free one!


BC
1960 Chevy C10 driver 261 T5 4.10 dana 44 power loc
1949 GMC 250 project in waiting
1960 C60 pasture art
Retired GM dealer tech. 1980 - 2022