1975 f 350 will not start, replaced the starter and silonoid and the battery is good, please put your two cents in!

 

Is there current on the solenoid when the ignition is turned to start? It should be tested on the "I" terminal(small one)? If there is not, check for a blown fuse, broken wire or bad ignition switch. It can also be the ignition switch adjustment is off not allowing current to the solenoid.