Working from memory (can be dangerous) I think I put a group 34 (12V) into the battery box of my C15A. It fit but without huge clearance in any direction. Looking at the sizes in a chart of BCI sizes found at
https://www.jegs.com/Sizecharts/bcigroup.html you may find the group 1 battery tall enough that the terminals could contact the cover for the battery. You measurements will tell the tale.