These adapters fit perfectly in my '67 Coupe. Absolutely necessary when installing custom seats (i.e. Procar Rally Series 1000). Hardware is included to bolt to new seat sliders. Good product.
Holes don't line up properly which makes for a very tight fit.
You will need to purchase the four bolts necessary to bolt the adapter to the floor, 4- 5/16, 1 1/2" will do the job
I bought these for Procar seats for a 1966 Mustang coupe. The passenger side track fit perfectly, however, the driver's side track didn't fit the seat or the holes in the floor. I wouldn't buy from Procar again after the difficulty I had trying to install these.