Power to manual brakes

Just want to ask if there is more than one length manual rod. I vaguely recall someone mention that. Or is it fine to use a manual pushrod from a 1973- 75 duster/dodge dart. My car is a power disc brake 1975 dart sport 360. I want to make more room in engine area and clean up the look under hood. I also read alot of threads where people on here ended uo with a high brake pedal. Please elaborate! Sorry for beating this old horse again!:(