Questions about the 4.9L 300

i was just wondering what is the difference between the 4.9l f150 and the f250 4.9l. is it just the gear ratio in the rear end? i got a 93 4.9l/5 speed f150 4x4, and just wondering if you guys might know what the idle RPM is? (mine idles around 850-1000rpm). and my friend says that their might be a ball at the base of the shifter that might be broken because when i throw it in reverse and floor it the shifter knob hits my knee, im not sure their is one.