I never saw a manual OHC-6 so I am unsure what the shifter was. But I had a 1967 400 Firebird, three speed manual. It was a Borg-Warner T-16 three speed. The shifter was actually bolted to the cross member. A stabilizing rod was bolted from the shifter to the trans. It was unbelievably sloppy. The trans was so unbreakable I used it whenever I needed a replacement for a four speed. But I used a GM ITM trans mounted shifter that came on my 1980 Malibu wagon. When I sold that trans I included both shifters. You can see the special shifter mount bolted to the tail housing. That made the shifter fit the 1978-87 GM A/G-body cars.I believe the 1967 Camaro three speed used the same sloppy set up the Firebird used. I am sure you could get a Hurst three speed shifter to work better. It may or may not fit the console if you have one.