Looking at the collision guide i see that they call em a "Vent Glass". I've always called them a "Wind Wing" Either way it's the small pie shaped glass on the front door, either side, in front of the glass that rolls up and down. It has a pivot point on top and bottom and is usually equiped with a latch. It sounds as though they will interchange. Never heard the term "Wind Split" before. Thanks guys.
Small Block