O500 swap
A-518 and A-500....
the 518 is based on the 727...500 based on 904....yes 500 is smaller because it is a 904 from the OD unit forward...but they both use the same OD unit...which where the problem comes with the sheet metal...
the correct numbers are 46RH and 46RE for the 518
and the 500 is a 42RH..