could someone please get me a measurement, bench seat 72 dart

I didn't try that, but the lever seems to work as it should. I'll check that out though, thanks for the tip.

I even had my wife sit on pass side while we both threw all our weight backward as it slid to try to unjam it if something was stuck (don't really like the brute force method, but I was stumped). I can see that the sliders are all the way back on their tracks as far as they will go (should have got a pic), so unless the whole seat was mounted too far forward somehow (looks normal to me), everything looks fine.

I use both of the seat belt buckles, but I'll check that out too, never even thought of an obstruction like that.

I figure when I install the new carpets, I'll go through this thoroughly, but if there was an easy fix, I'd like to find it now.