Left rear brake drum gets hot

On my 1967 plymouth valiant, Im experiancing issues with the brakes. I did an 8-3/4 swap and put the 11 inch shoes on the rear. They seemed to work great until I had to swap out the third member due to noisy gears. At first I thought I may have over adjusted that side, but it turns out it’s adjusted fine. The drum comes right off, and has very minor drag on it. The springs, shoes, and wheel cylinders and drums are all new. The car developes that overheating brake smell, and the left rear drum gets to 250 degrees while the right reaches 80 degrees. The fronts are discs and run around 140 degrees. This is on a 35 degree day. If the drums aren’t over adjusted, what would cause just one side to run hot?