1963 dart heater box??

the 63 dart project, all it has is the 2 sides of the heater box and a heater motor. question is what other darts or cudas will have the same box???? I have access to 65 dart and cuda . will they be the same??? thanks for any info...
also wondering on the early a body heater delete cars, what did they block off the hole in firewall with??????