Chopper, a thought just popped up. If you could get a spacer, that woud stand off the fitting that screws into the head, that would probably give you enough extra to clear your motor mount. A flat washer may work, but don't short change yourself on threads into the head, they will strip out kind of easy. Also, the capture plate, the one that screws onto the muffler, needs to be able to turn slightly for alignment. I at first though of a nut off your old manifold, but I'm not sure that would leave enough threads. You may want to check it out though.

Don