These will fit 65-73 911/912. Purchased new last year and lightly used. Corbeau part # C22014

These could be easily adapted to other brands of seats. The sliders bolt to the square frame that attaches to the car so you could move them anywhere you want to get the correct width for your seats. The current spacing for the width is 11-7/16 inch.
As for the length (front to back), they are currently spaced 13 inches and at the max length of the sliders, but you could drill any length less than 13 inches to match your seats.
The height from where the frame bolts to the car to the top of the sliders where the seats mount is 1-3/16 inch.

$160 shipped for the pair