1975 Dodge Dart Idler Arm

Well you've already found the cool trick. Grind the head off the bolt and install from the bottom. The issue is that if the nut backs off and the bolt falls out, you'll have no steering at all.
The right way is to loosen the motor mounts and jack up on the engine...that's not what I did :lol: but I did drill the bolt for a cotter pin just because I'm a "what if" kinda person.