Some race-only Panteras relocated the tank to the front rrunk, but they used full tube frames DEnnis Quellas fiberglas clone-Pantera uses this arrangement. If you did this with a stock Pantera, I suspect there will be a LOT of cutting required to get a same-volume tank in there. And the front trunk as it is now, is also the bracing for the entire front suspension as well as the main deflector for hot air exiting the radiator. A smaller volume tank could be fabricated to fit as-is, but that high-mounts the fuel load (gas weighs 6.8 lbs/gallon) and requires the battery to be shifted to the rear which partly zeros out any gains from moving the tank.
FYI, the factory LeMans racing Gr-4 Panteras ran two 12-gallon fuel cells, one on either side of the engine rather than a wholesale shift to the front This improved the cross-car balence, allowed short fuel lines and didn't force a change in the front suspension bracing.
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