Leg Room Mod
MW Note: Shown on 96 - 98 Chassis below
It's no secret that Mustangs are a little light on legroom. There is a fairly easy modification you can make to give almost 2 inches of extra legroom. This does not require any changes to the floorpan or how the seat adjusting mechanism attaches to it. It only changes where the seat attaches to the top of the seat adjusting mechanism.
The before pic shows where the seat sits full-forward in stock form.
First remove the four large bolts holding the seat onto the floorpan. Depending on the type of seat, you may have to take apart some electrical connectors. Remove the seat and find a clean spot to place it bottom side up. Remove the four small bolts holding the seat adjusting mechanism to the seat bottom. You will then see the extra holes (4 on each side) at the back of the seat bottom.
You will be moving the mounting bolts of the seat adjustment mechanism from the 2nd hole in, to the 4th hole in. Ideally a tapping set would allow you to put threads in the new hole, but i found this not to be necessary. With the seat adjusting mechanism removed - thread the bolt into the new hole using a socket wrench and short/firm turns of the wrench. Do it slow and steady and make sure the bolt goes in straight.
For the holes at the front of the seat bottom a new corresponding hole must be drilled into the aluminum bars on each side of the seat adjuster framework 1.75" back. The bolts will go through the new holes in the aluminum bars and into the original tapped holes at the front of the seat bottom. Measure(carefully!) and mark where you will drill the holes on the bars. I used a 5/64" bit to start a pilot hole, then used a 1/4" bit to widen it and finally a 3/8" to make the final hole.
Mount the seat adjustment mechanism into its new location on the seat bottom and reinstall the seat back into the car. This modification will move the seat 1.75" further back. But it looks and feels as solid as stock. Keep in mind on manual seats the adjustment handle will stick out farther from the seat than normal, but it is not that bad and could conceivably be cut and remounted if you feel it is out too far. On the difficulty scale of 1 to 10, this is about a 4. The process took about an hour and a half per seat.