the 351w will fit but you do have to use a hood scoop on the ll. it will bolt to the stock V8 mounts, but you will need a custom oil pan, and you will either need to use the Mll 302 flexplate/flywheel, or you will need to massage the tunnel for clearance. you guys miht try
www.mustangii.net/index.asp i found them when i was thinking of replacing my grand marquis with a mustang ll.