Column shift to floor shift, some of the differences is shifter on the column and floor shift has no shifter on it it of corse. Power steering is a shorter shaft and manual steering is a longer shaft. The steering units take different couplings. The power unit is a smaller spline the standard is bigger spline. So you need a column with no shift lever on the column, and to know if it's power or manual steering for shaft lenght. There are some cosmetic differences in year models but for the most part, all E bodies do interchange. The harnesses will differ from ac to non ac being larger