I was reading a MM/FF issue this afternoon and found some stuff that might help you.
www.wildridesracecars.com has torque box mounting point reinforcements for about $140 and Laurel Mountain Mustang(Rt 2, box 163, Sunny Drive, Ruffsdale PA 15679)(Fax 724-696-3234)(phone # 724-696-9665) has floor pan reinforcement used on ploice intercepter stangs for $24.95
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1990 Dodge Dynasty with 275,000 miles. Mods:chiped paint, CD player. Sucks but it was free. Praying for a stang.
The "Guetto Glider"
If it ain't broke, you ain't tryin hard enough