1970 C10 Trans Issue after distributor upgrade

[rmawyer]

Work done by a buddy with decades of experience. We finished late in the day and I did a short test drive around his neighborhood before heading home but did not get up to speed until I was on higher speed roads later when driving home. I called my friend and explained the issue, and to his credit he said it sounded like the transmission modulator or line. Since I could not get the truck back to my friend for a couple of days due to a funeral I used that time to contact my friends on the forum to get their opinions and of course they corroborated my mechanic's diagnosis. Just covering bases - thanks.