Upholstery Sewing Machine?

Pfaff and Merrow industrial machines are fairly common here is the south where the textile industry once thrived. The problem with those ancient workhorses is the cost of replacement parts.
I should add that you are about to enter a whole new world in seat skins. They fit tight as a banjo string when done right, especially vynil skins. I've seen countless listings on ebay that stated "new Legendary seat covers" and the pics show wrinkles on the sides of the seat backs, lines skewed left or right, etc... Even those correct fit covers were not properly installed.
I mention this because the tighter the skin fits the stronger the stitching and bindings needs to be.
Good luck with it.