The Harley Davidson part number 66010-97 has had four OEM upgrades over the years. They append the letter A, B or C after the number when a newer, perhaps higher crank version is available. The physical size of the 66010-97 battery remains the same.
Remember to take into account that the CCA is not the only metric you should pay attention to, the Ah or amp hour capacity is vitally important and arguably more important for today's Harley motorcycle. If both these numbers are higher than what OEM specs indicate, you know you have a solid battery that will stand the test of time. Our Baseline AGM flush-mount Harley battery is the EXT Magna Power series by the Harley OEM manufacturer East Penn Deka. Our alternative advanced AGM product is provided by MotoBatt and Braille, with Braille being the best Harley Davidson battery replacement option.
The 66010-97C battery has been used exclusively in the FL and FLH Harley Touring bikes for many years.