Question about shaft style stereos

I used a lot of Pioneer, Kenwood, and Alpine stuff back in the day and was pleased with the quality. I never had an issue with the shaft spacing, and I did a probably a dozen or more car stereo installs over the years. If I recall correctly, there were some units that had an adjustment mechanism to change the shaft spacing if needed. If I could find a good (maybe new???) shaft unit I'd snap it up in a heartbeat for my 66 Valiant.