- "He [Marty] paused and frowned in at the mass of wires and vacuum tubes that now was mounted on the hood of the DeLorean. That, and the big fifties-style tires that Doc had mounted on the car to replace the ones that had shredded with age, made the DeLorean look like one of those so-called 'funny cars' Marty used to see when he went down to the Hill Valley Speedway."
- —From Back to the Future Part III by Craig Shaw Gardner (quote, page 34)
In order to replace key parts from 1985 that would have existed in 1955, including the destroyed time circuit control microchip, Doc worked from the schematic diagram included with the repair instructions to fashion a boxframe unit that was attached with straps to the hood of the car, which included a vacuum tube assemblage that helped control the time circuits.
- Back to the Future novelization, page 114