- the back seat was completely eaten by rats, the foam is gone, the black vinyl covers will be replaced with nugget gold ones.
Try NPD
http://www.npdlink.com/ They at least have the seat pad, burlap and edge padding. You can also get a 1968 Mustang Interior Assembly Manual that details what to do. THAT LAST IS MANDATORY.
Then let your fingers do the walking in the yellow pages. Find a local upholstery shop and buy some foam. You may need two different thicknesses.
Or -
Find another seat from almost any 64 thru 73 Mustang hardtop or convertible and strip off what you need.
For tools - Amazon. (I used a search engine to find "hog ring pliers" on Amazon and other sites.) One of the top quality pliers is made by C S Osborn. Don't skimp on a $11.95 pair of hog ring pliers. Half way thru your project, they will fail. A good pair of hog ring pliers are $30 and up. Harbor Freight used to have a decent set, but their quality has slipped.
For hog rings - Amazon, 3/4 inch. Yor will need about 70 for the base and 60 for the back.
To remove hog rings, I use an end cutter, a large end cutter.
When (and if) you get to the actual installation of the vinyl cover, leave them out in the sun for an hour to make them easy to stretch into position.
Jim