I made this same conversion for my project, 1969 Pontiac OHC Sprint in a 62 Nova. I used a mount that came with a floor shift kit from J.C. Whitney, Mr Gasket #7666.I used a Hurst 3 speed shifter, the one in the kit was less ideal. I modified the mount so that the shifter would come out in the stock location using a floor hump and provide clearance to the floor. I do have pictures if you are interested. If someone could tell me how to post them here I will, or e-mail me.
Carl Stratton
Inliner #3580
e-mail firebirdst@yahoo.com