Help for installing RPM tach on my 65 dart

Pic shows you dont have a fuse clip at the radio fuse port either. If you're going to rob parts from a donor fuse box, may as well put the accessory/tach wire in the correct place.
If you dont want to aquire and install fuse clips from a donor box, there should be a unused spade terminal on your windshield wiper switch. That's a switched and fused power take off also.