Awesome job boys. As always, information is King.......... We have no idea what transmission you have. I will assume a 3 on the tree Chevy original. If so, you are on the right track. You just need to have one guy under and one guy shifting at column to see why lever does not fully rotate from linkage movement. More info, your observations, and our experience are all we have to figure out problems from our house.
On a 3 speed, the 1st and reverse are the same lever, so it makes sense that particular linkage needs tweaked. There are shift lever bushings and other linkage parts available depending on year and model of trans. Post some well lit, good pics of trans/linkage if you wish. Use the Attachment Manager at lower left of each edit screen. If you are vetted.
