I have an 84 F150 4x4, 351W, 4 speed trans.

Every now and again when I start it i can hear the starter go but, it kind of grinds. Doesn't sound like its engaging all the way. I know the bendix unit in certain starters can go bad so I'm hoping its just the starter and not that the flywheel isn't all chewed up.

Could this be anything else, possibly a connection running from the ignition key?

 

Make sure the starter bolts are tight. If they are tight and it's still grinding...time for a new or rebuilt starter. Rebuild kits are cheap and easy. Starters are cheap & easy. While you're at it, clean all electrical terminals from starter to solenoid to battery as well as ground wires to ensure good connections through the system and longer starter/battery life.

 

it wouldn't hurt to check your flywheel. might save you some frustration