1947 Plymouth Special Deluxe

I'm going to be redoing the interior with a black embossed vinyl where you see the grey color, and I don't know what else to replace the red areas.

I really don't want to offend you. - And I'm no expert on upholstery. But I can't see the red/white pattern ever working unless the rest of the car is done crazy wild. My personal opinion (for what it's worth) is that I'd have to tame it down. The gray portions don't bother me. Especially because they blend with the painted gray areas of the interior. I could see leaving the gray alone and changing the rest. I don't know what your plans are for exterior color, but even if it is going to be red I would have gone with an un-patterned material that was pleated or maybe a tuck & roll.