[Jack21]

All depends on which motor mounts are in the car now.

If late model '80's - '90's 5.0 mounts now, lift engine up enough to get old mounts out, and new ones in. Might have to take headers off to get at the mounts. Could even do one side at a time. Trans mount is an easy swap. Mounts have one 14mm bolt pointing down at a 45* angle. Save these bolts as new ES mounts don't have them.

If older style cross bolted mounts are used, you have some fabricating to do. If frame mounts are welded to frame, it may not be worth the effort.

I'd contact BRM before going any further.