I do not know what more I can add as far as info ?
Well, how about the frame type? Original? Reproduction? If reproduction, who is the manufacturer? What kind of front suspension do you have? Mustang conversion? Corvair? Custom?

There are at least 25 shops that make frames and suspensions. Whithout some hint as to what you have, there's no way to answer the question.

Anyhow, if you shorten only the lower control arm, the top of the wheel will tilt out, and your problem will get worse.

You might want to see if you can get front wheels with less backspace to tuck them in closer to the chassis. Not cheap, but cheaper than four new control arms and a front end allignment.