Aluminum Master cylinder applications

From what I read you can pick up the MP master cylinder for big bucks or cheap ou and find the correct application of the same Master cylinder in a rebuilt unit for half the price. I read any 79-89 vehicle? I already have manual brakes so I dont think I need the big 1 1/32 size. Also What about the rods. I see magnumHP sells a master cylinder machined with some special retainter you need for manual brakes? Just not sure what all i n eed here.