The Ray Sphere was a device used by transferring the neuro-electric energy from a group of people to concentrate it into a human indevidual to unlock his/her powers. Though it will unlock the dormant abilities of the Conduit, it will kill the catalysts, and worse, cause a catastrophic explosion.
How many gallons of gas does the average mid-size car hold? The average fuel tank size for mid-size cars is 16 gallons. If the  price of gas was $3.59 per gallon, it would cost $57.44 to fill a  16 gallon tank.
The standard tank appears to have been 26 gallons, although there's a bit of confusion between US and British sites about whether that was 26 US gallons (which would seem logical, coming from a US manufacturer) or 26 Imperial gallons (which would equal 31.2 US gallons). Sources: 1964 Cadillac Specifications.