[5.0 in a 66]

You'll need a V8 rear, either a stock 8" or, if your running a lot of power, a 9". You'll need a V8 radiator, engine bay wiring, and front brakes. I'm not as farmiliar with doing this on a 67-68 as I once was, so that might not be a complete list. Rest assured that you have a lot less to change than on a 65-66.

USUALLY collum shift trannys just need the main linkage stub flipped the other way for floor shift, but I can't desciribe this very well.

Stay away from MU. For that matter, stay away from Mustangs Plus (**** are they ever expensive!) Try NPD, K.A.R, or Ponderosa Mustang.