A500 or 727 trans?.... Need help to identify...

I am starting on the process of swapping out my 318 for a 360, the donor truck is a 1989 3/4 ton. It does NOT have an overdrive tranny... At least as far as I can tell. It is no longer driveable, and I did not recall it shifting into an overdrive. And it does not have an overdrive indicator on the selector. So... I got up under there and took a picture of the pan (thanks dart-doctor for posting the diagrams) and to me it looks like a 727. I measured from the bellhousing to the tranny mount and came up with 23 inches, could have been 23 1/2. I only got one decent pic of the pan (see below) but could this be an A500? I don't know what an A500 pan looks like, that's where I need your help...:happy4: