King (2bking) on FFCars.com designed some sheet metal that modifies the footbox and firewall to better accommodate the Coyote motor in the Factory Five Roadster.

The modifications allow for more room near the top of the motor and kicks it into the interior of the car, then kicks it back out of the footbox at the bottom leaving more room for your feet. The modification also angles the front of the footback a little to leave more room for headers to make the tight-turn when exiting the side of the car. The chassis has to be slightly modified to accommodate this new angle.

King offered a group-buy for 8 of us to get them made by a fabricator in Atlanta for a steep discount. Here is the fabricator’s info:
Brad Stell
Stell Enterprises
14049 Hwy 231/431
Hazel Green Al. 35750
256-603-0253
www.stellenterprises.com

I ordered a set with two extra-thick .090 aluminum firewalls, one of which is modified to be pushed forward to give more room behind the dash. I had previously ordered a Firewall Forward piece from Linwood at FFMetal, so I had King design up a new one to mate up with the new Coyote Footbox sheet metal.

Here was the cost breakdown:
$116.00 for set parts
$8.00 for .090 firewall upgrade
$58.50 for Firewall forward,
$15.00 for packing
$30.24 for shipping
$227.74 Total

Everything came in. Looks like the firewalls need a little trimming. I’ll do that and modify the chassis later with some help from some friends, before sending the aluminum out for powder-coating.

Here is a PDF schematic of the FFR MK4 Firewall Forward modification by King to mate up to the newly modified footbox. I’m providing this without warranty in case it may help someone else interested in doing this.