The cause of this is that the steering wheel is sitting further down in the shaft. After installation and the bolt is being tightened; the tightening is actually drawing the steering wheel further down in the shaft , allowing the horn contact to be
touching more. So, when turning the wheel , the horn will sound intermittedly while turning. With a steering wheel puller
pull the steering wheel out a slight amount until the horn makes no sound while turning.
I had this happen to me 20 years ago after I replaced the turn signal switch. Put the steering wheel back on, tightened it , then the horn would sound intermittedly as I turned the wheel. I used the steering wheel puller and pulled the steering
wheel back a tad until the intermittent sounding would stop. I may have moved the steering wheel back maybe 1/32 of an
inch. But that's all it took. This was on a 68 Coronet.