Difficulties Installing ABS Headliner in 73 Swinger

As Jpar suggested, make sure it’s tight against the roof before you start trimming it back. Installing the dome light will help, pushing it up into place and then clamping it will help. It’s hard to tell from thr pictures but it looks to me like it’s not pushed up against the roof along the edges, it stays flatter as it transitions from the roof to the edge leaving a gap behind the headliner. You want to push that out before you start cutting.

Yes, they’re expensive. So are the replacement cardboard ones, and they absorb moisture. Yes, they need some trimming to fit perfectly, but that’s true of darn near everything made for these cars. Which is why I suggest getting them without any upholstery. The other reason I suggest getting them without upholstery is that the glue they were using a couple years ago wasn’t great, and I had to re-glue pretty much the entire headliner fabric on mine after it separated in the heat. So yeah, they definitely have their issues, and at full price I can see why some folks would be disappointed.

I still like them far better than the cardboard or the earlier fabric headliners, but that’s just me. The last one I bought for my Dart was from amazon and it was on clearance for way less than half what they usually sell for, so deals can be had. All the interior stuff for any of these cars is insanely expensive. Legendary’s stuff fits well, but costs an arm and a leg. PUI has plenty of complaints and issues, and they still cost a heck of a lot of money. Just less than legendary. For me it just boils down to I’m not doing custom upholstery myself. Not what I want to spend my time doing. Could I make something cheaper? Sure. Would it look better? Probably not. And it would take forever. That’s why I spent the money, and it’s why I tell other people the issues I had so they know what they’re getting into.
I'm almost positive you seen my thread where I made my headliner? But anyways with a pretty good idea of how it's done and what to use I can't imagine it taking more time than it would to order one and wait for it and get it open it and test fit it and recut it again and again. I would be thinking at this point it's going to have to be taken out and it's going to have to be putting back in and it's going to have to be fitted a couple times and test cutted. And as you say you're going to have to want to glue the headliner on also...
I know this doesn't help the original poster or any but if you're taking your headliner out anyways and to give it a $15 shot to slap it down on a piece of 1 ply plywood. Cut out a replica of your old one. Get a $15 can of that glue spray and $15 worth the headliner material at Jo-Ann Fabric and Valla...
As far as the time scale I would think most anyone within a half hour of a city limit could be to the lumberyard in Jo-Ann Fabric and back home within 2 hours and since the headliner is out you could slap it down on that plywood trace it and cut it out within an hour and I think you're already at about where you're piece of plastic comes in for $300? Just for conversation sake? Also I do agree with everything you're saying about the headliner it's not easy either way or...
IMG_20180301_162640.jpg