I thought that was the case. So...in that case.....you would also need to change out the drums, the backing plates, and all the brake parts. Unless...of course....you redrilled the 4-lug drums and made them 5-lug.
you would want to buy ...new 4 lug drums ...to drill...and hope nothing happens on the road that you would have to ...replace a rear drum... if so you would need a. ...spare 4 lug axel... ...spare 4 lug drum... ...spare 4 lug tire and rim with that thought, i put the 5 lug rear out of the parts car in. ...as always...JMO...:Handshake