My experience I was the same. I used the rear mount bolt to make a bushing rather than drilling the engine. Different method, same outcome. I had to buy front lower mounts because as Spectra said, they project forward rather than to the rear and rub on my Mac 2 into 1 pipes. Actually they clear by about the thickness of a business card. I also had to remove the rear master cylinder mount from the old frame and weld it to my 80 frame. The triple tree and swing arm fit with no problem however in my case the plastic inner fender on the rear had to be modified to clear the battery box. In my case the 77 frame as well as the entire front fork was severely damaged in a colision with a Jeep Wrangler. In short it can be done with a little work and ingenuity.