The side motor mounts are no problem with a number of shops making "kits." The question become one of where the mounts go relative to the frame. Both fore and aft and up and down. The only way I see is to "dry fit" the motor, but given the length difference what does one use as a reference point.
The next question is the trans mount. I had thought about trying to move the cross member back, but clutch and brake pedals and linkages will have to move. The idea of a second cross member does not support (no pun intended)my goal of having everything "look" stock.
My plan is to position the block relative to the firewall and see where things lay.