Guess what... after all these years, I just discovered that the basket-case Dart (literally, it was stripped and all the parts in boxes and bags) came with the wrong windshield! It's an inch taller than the opening in the car, let alone the thick rubber gasket seal. I kept staring at it, thinking I put the seal in backwards or something obvious, but the measuring tape doesn't lie. It is definitely NOT going in today
I can only assume that the PO included in the pile of glass a windshield for a sedan and not my '72 2-door hardtop (Swinger). It's "close" when eyeballed, the curvature and the width looks correct but it is definitely too tall.
Tomorrow I'll call local glass shops and see what THIS screwup is going to cost me... they go for around $189 on Ebay but the shipping is horrendous. Sigh.