Amd's Dart Full Front Floor Pan 4 Speed?

So I live in the wonderful land of Canada, where the beer flows like honey and the rust wrecks cars faster than the Duke boys can.

So needless to say I need to replace my floors. Right now my 75 Dart Swinger just has the original 318 and the 3 speed torque flight but I'm planning to put in a 400 and 4 speed in the near future.

I'm wondering if the floor pan part number 400-1067 by AMD will work with an A833 or do I need to buy the extra tunnel piece part # 415-1067?