The later Panteras with factory drop flor pans have a virtually flat floor, no bracing other than a front to rear strengthening brace between the seat bolt holes.
The pedals are the same ones in later cars with dropped floors, so why would it be an issue here?
I take it this is a race car, for which I assume you'll install upgraded brakes? So why do you even need a brake booster?
I don't have boosters on either the Ultima or the GT40. The Ultima has excellent braking (AP Racing), the GT40 being C4 Corvette brakes does take some pedal stomping to stop in a hurry, but that is partly due to the pedal position at present as it currently has hanging pedals which I'm going to change to a Tilton floor mount this winter, plus switch to Wilwood calipers. Both cars have dual brake masters with adjustable bias.
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