now it makes sense why all yours are 3:1. I have about a dozen tank and all having 3:1 would be an expensive proposition. I'm just putting a Matorro 3:1 in my Panther. It was the one designed for the M41. The Panther required the longer shaft like the M41. However the holes to secure it are different so l will have to use milliput to form a new foundation to secure the new boxes boxes.