I have a 3 speed with overdrive in my 1966 GMC. If you can do a bit of cutting, drilling and welding, then you can tackle this. The Hurst brackets are fairly universal and have a number of mounting holes to try out. I mounted my shifter a bit higher than the ones in the pictures and I didn't need to put bends in the shift rods. I have the later overdrive with synchro first and 7 bolt side cover (sweet addition, by the way!). I don't have any pictures, but let me know if you need me to crawl under and take some. I ended up making a shift lever handle rather than using the Hurst handle. It got the lever right where I wanted it and has the look of the original 4 speed levers.

I hope this is helpful. Here is the original literature on the web on these transmissions, if you want to read up on them.

http://speedprint.com/deves50/overdriveindex.php

Regards,
Steve
New Orleans