[Angel And The Wolf]

Seems like the solution! I should be able to put this in the spare tire well, cover it to seal it from the interior, leaving the fill cap exposed for filling. (yes, a second fuel filler flap on the fender of the car would be preferable) being sure to provide venting to under the car, turn the car off for refueling, wipe the filler opening well,and be safe from electrical caused explosion.

Ideal would be to slice into and weld to the car's fill tube, and keep the whole race tank isolated from inside the car, but that's a higher skill than I have just to save 50 cents per gallon.

Any better ideas?