Doug,
The Tmcc F7s have to be lowered about an eighth inch to solid mount the pilot and have everything look right .My first B unit I just cut the mounting tabs of the shell which requires the doors to be modified and non working. I think I did a tutorial on it.
I've looked at modifying the truck rings and I think they will have to be cut or ground and new center section attached. Haven' gotten back to the Fs due to the Alcos and now the steamer ERR installs. Sometime soon though.
Ron