All of the above info is correct but only applies to 4 1/2" bolt pattern stuff.
I found a 4" bolt pattern 9" drum 76 Dart last year. Car was a 4 door /6. Story I got was 4" b/p stuff was used on 4dr /6 cars only as far up as 76.
Never say never with any of the older stuff...
As earlier mentioned I've never ran across a 4 1/2" bp with a 9" drum...
I owned a 76 Dart 2 door, slanty automatic. 4 wheel 9 inch drums NON power, small bolt pattern.
One hard and fast rule: All 4 wheel drum A body cars were small bolt pattern, every one EXCEPT the Hurst Hemi 68 Darts and Barracudas.
I don't care what the service manuals list, I have personally seen 9 inch front drums on enough 73-76 cars to know that it wasn't all the result of owners changing stuff around. What are the chances that 10 or more people just in one part of my state decided to remove 10" drums to swap 9" versions on? It isn't as simple as changing drums...The spindles are different along with the control arms. This makes DOWNgrading from a 10" drum or 11" disc (Which too many people incorrectly state as being the only possible combination) as a swap that would also require awheel alignment. Think of how little sense that makes.
