Are you using a vitesse prop? They fit with d type, but too tight for j type.
Best solution is to have the prop shortened.
However, I had the same issue years ago, and needed the car for work the next day. So I made some spacers to fit on the engine mounts from a bit of box steel. Think I had to space the rad forward too, but as I said, it was a long time ago.
Re mounting, I made mine, easy to cut/drill etc. But get the height correct!