You are a long ways away from here , however have you tried your local auto wreckers for a good used one.? I know you can still buy them new from your Ford dealers here as well as just about any auto store. The real olds ones I think were thickers though, not as plyable as these newer one.
You most likely do not have to be reminded of this but you should have a ground strap installed with any of these liners as well.May save your butt some day fill a jerry can in the box. Sorry, I forgot I was snooping in your forum, nice cars and nice shop.