I also have a friend that's putting these in a '66 Cuda. He says the instructions say to move the motor to the passenger side by 3/4". (Glad i asked as i bought mine from a guy in Hawaii on ebay...no instructions). I assume thats what you've done. The factory already has it over by 5/8 and I don't want to go any further. RMS sent me 1/4" offset motor mount bushings, the result being what I have pictured. I'm removing the driver side shock mount, moving the inner fender metal and notching the frame rail for room.
It's a *****, but I love this stuff! I appreciate everyone's input.