Random but violent front end vibration

72 demon 340
73 disc brake setup on front. Other than that stock suspension setup. Cars been done for quite awhile but just not a lot of miles on it since restoration. Probably 200 miles over the past 3 years.
Vibration has happened twice in that span of miles. Comes on out of nowhere and shakes the dash pretty bad. Both times i slowed down and turned and it was gone. I m pretty sure the vibration started about a half mile or so after a stop. So i was leaning towards a caliper but there was no noticeable pull left or right. I ve had it up in the air and checked for loose nuts and bolts but all were tight except for the passenger side upper balljoint i got about another half turn on it where it bolts through the upper control arm. The wheel bearing nuts i put a little more tension on. Thats all i could find. I haven’t had time to drive it since then but I don’t think any of that is gonna fix it but its so random when it does happen god knows when it would happen again. If anyone has any suggestions i m ears. I ve got a 3 hour drive to Columbus coming up pretty quick. Thanks in advance