The C-6 tranny would be a nice piece to hold on to. The block would be ok, but is too tall and needs to be cut down. I would keep all the accessories and brackets. The heads would make good door stops or paperweights.
A 460 will slip right into a 71-73 mustang, matched with a set of 460 Edlebrock heads it would make quite the hot rod.
Like I said, the engine runs, but should probably be rebuilt.
Should I hop it up, or is there enough snort in the 460 to just leave it alone. I may put it in the 73 Mach. That 351c runs fine, but what the heck...
Engine & trans are a bolt in for your 'Stang. Make sure the center section is a 9" not a 93/8" & keep it too. Most of the rest isn't worth a hoot unless you need parts for a Lincoln. Engine mounts are the same as a 429/460 in a '72/76 Montego/Torino/Elite. It's a fun swap, I've done many. If you wanna hot rod it the heads will have to go too.
Engine is a keeper but probably not the tranny. Most C6's found in the continentals had an extended tailshaft that adds even more length and weight (I learned this the hard way and now have a hundred pound paper weight sitting on the workbench). A stock 460 is nice but there is a ton of performance pieces to really wake it up.