can't crank with key

This might sound too simple, but do you have the ground wire connected? When I first got my 66, the yellow and black wire was cut and and the previous owner rigged up a cheezy push button set up to start the car. I got the yellow and black wire hooked back up and it still would not start with the key. Then I looked at the wire diagram and noticed a ground wire. Hooked it up and started on the first crank. Now the car's in pieces!!=P~