how wide is a c3 frame in this area

[JeffP1167]

middle of doors side to side?

 

[68/70Vette]

I have bare frame in the garage and a tape measure sitting on top of the tranny. Where the doors are, the frame is 55 1/4 inches on the outside and 48 inches on the inside. The inside of the frame is sloped, so the 48 inch measurement is for the bottom inside of the frame to the corresponding bottom of the corresponding inside portion of the other side of the frame.

 

[JeffP1167]

thank you