In anticipation of winter, I decided to change out the 2001 Corolla battery. The battery guides and even on-line selection tools all say it takes a Group 35. To my surprise, the car has a Group 51. It doesn't look like a 35 will fit the mount that's there. Is a 51R-4 an equivalent? I'm old, so I don't remember, but I assume that I had the battery changed before this. Is it possible a shop switched to a smaller battery and put in a smaller mount for it?