They will be the same between the Invader and Intruder, however, there were some differences between years. I believe the 78-79 have a different type of bearing on the clutch side of the jackshaft, this bearing has a different ID so the jackshaft is different as well. The 80-82's have the updated (and better designed) bearing and housing. They are all interchangeable, but you must use the bearing, bearing housing, and jackshaft together. You can't mix them.
Sounds like a great couple of sleds! Good luck!