Four bolt to five bolt conversion/8" Ford axle

Just get the axles/drums drilled? Or?

 

or get axles from a ford ranger or small van aerostar? i believe you use 2 drivers side axles

 

the ford 8'' and 9'' axles will interchange just make sure you get the right length and number of splines 28 or 31

 

Ok, here is what I know. There is no direct interchange to a 74 to 77 Mustang II 8" rear.

However, the axles in a Maverick are 17/64" shorter on the right side, and 9/64" shorter on the left side. These will probably work.
Better yet, the axles from a 63 to 65 Falcon, Comet, or Fairlane, or a 64 to 66 Mustang with 8" axles are 1/4" too long on the right side, and 3/8" too long on the left side. Measuring several axles I found all of them had enough splines to be shortened this much. And it doesn't have to be done on a lathe, it could be done with a Skil saw and abrasive wheel, then rechamfer the end of the axle.
Also 57 to 59 Ford with a Non-heavy duty axle, everything except police, taxi, wagons, ranchero, and some convertibles, are 9/16" too long on the right, and 3/8" too long on the left. Again the axles can be shortened that much without hurting the spline length. The wheel bearing to flange length on all these are the same, and Maverick drums will work with the Mustang II brakes. All of them use the same wheel bearing, and bearing retainer. The bearing collar on some is different OD, but will interchange on the axles.
I suspect, that Granada and Monarch axles will fit with minor shortening also, they are in the range of the 57 to 59 ford, but I couldn't find a listing in the books I had.