I'M A CHASSIS BUILDER AND EVEN THO THERE ARE NO RULES ON SEAT TRACKS,IF YOU USE A FULL HARNESS AND HAVE AT LEAST A ROLLCAGE IN IT THE SEAT SHOULD BE UP AGAINST THE REAR BAR.YOU WILL NOT BE SAFE IF THE SEAT IS NOT UP ON IT WHEN YOU ARE BELTED IN. IF THERE IS A GAP THERE THE SEAT WILL MOVE UNDER IMPACK. MAKING THE BELTS LOOSE.