I bought a '25 dodge cowl and grill shell at an auction a couple years ago and to day I picked up a '20 dodge roadster back half, they're close enough I can make some doors and have a roadster body, body isnt too bad for its age. I worked a little on the trunk lid today, as you can see in the second pic the inner rail was twisted, turned, spun and down right anything but straight. I popped a few spot welds and a few minutes in the vise with a pipe wrench and hammer and now it fits really good, got it all clamped in to weld fast tomorrow
I hope you can deal with the width difference at the sill level. The older cowl tucks under to match the older roadster back you have. I have pieced a couple of pre 24s together for a friend near here. He says the early cowls/doors are very easy to find?
F&J looks like it wont be hard to match up, I meen after all its just metal right? a little cut here a little weld there and bango its a roadster, lol Im not sure how hard doors would be to find, Ill probably just fabricate them up, I think itll be easy to blend the two different years that way.
The doors for the early version have rounded lower corners at both the front lower and back lower. So, your homemade "blending" doors will be a rounded at rear and straight at front edge I never had to try the swap you are doing. The guy did have me put a rusty woods-found cut off rear roadster turtle piece onto the back of a 21? cut off roadster. He did not even know why that back was a bit different, but where the cuts were,( just in front of the rear fender) it fit pretty decent yep, it's just metal...and no wooden sills, which is better for me.