starting issue

I have a 1973 Charger 400 Non SE and I am having starting issues.
It seems The Engin will crank and crank, but only wants to start when I release it from the Crank position. I have to find the happy medium between the Crank and run position for it to start. Once the vehicle is warm and drive it around, the vehicle starts right up most ofthe time. I have alreay replaced the solonoid on the firewall on the drivers side. I think its the Ignition switch, but not sure. Will I have to replace the Key tumbler too? Any other advice is greatly appreaciated.

Probably your ignition switch is bad. No, you won't have to change keys

I had that problem and it was a loose wire at the electrical bulk head on the firewall.
Good luck!

I had this problem on a 81 pickup.
the solution was in the battery cables. they were #4 stock guage cables but the starter took the majority of the current leaving very little for ignition. in fact I was getting one spark as I would release the key. the whole time cranking, no spark at all
upsized the cables to #1 guage an got consistant spark while starter is engaged
and the thrill of victory...