To followup on this issue, the High Hump is seen in the first picture of a 1960 C10 3-speed on the column and the Low Hump is seen in the 2nd picture of a 1962 C10 Suburban with a 3-speed on the column. The Green arrows point to the humps and the Yellow arrows point to the firewall pan that the hump connects to which is spot welded to the cab. These firewall pans are not interchangeable so the cab either comes with the high or low firewall pan from the factory (unless someone changed it after-market).
