Well, I know the sedan and the coupes share the same frame.  Last fall I helped take a 4 door sedan body off a frame so a friend could put it under his coupe.  His coupe frame was damaged in an accident, and the 4 door frame was the exact same.  If the convertibles are like my 58, they probably have the large X member to help reinforce it.  Lee

I have restored a '41 coupe frame and have been under a '41 convertible. The convertible frame is not the same. I don't remember all of the differences but I know the convertible frame has more structural supports built in.

The 1936-42 service manual shows only one diagram for 1941 and one set of dimensions. So if they are different then it would be a matter of reinforcements that weren't shown in the diagram.

Can anyone tell me if there is a difference between the frame on a 41 bus coupe and a 41 convertible? I read that they were the same, but someone told me there is a difference.