With Aaron headed to Pike's Peak again, he tasks the Monkeys with building a '55 Chevy in less than two weeks when Richard plans to sell it at a Barrett-Jackson auction, among about a million dollars worth of cars.
As Richard gets ready to sell a million dollars worth of cars at the Barret-Jackson auction, problems arise with his '55 Chevy threatening to keep him from taking it to the auction.
Betting on a speedy build because of all the aftermarket parts available for G-Body cars, Aaron decides to bet Richard that he can finish a 1980 El Camino in three weeks instead of four.
Just when Aaron thinks he can win a bet against Richard, last minute problems threaten to push them past their deadline to finish a 1980 El Camino one week ahead of schedule.
With Aaron set to take off soon for a long-deserved vacation, he and Richard get the Monkeys started on giving the "proper" treatment to a '65 Volkswagen Beetle.
With Aaron on vacation, Richard lets the Monkeys give his first car he owned in high school the Gas Monkey treatment, a '74 vomit green Mercury Comet.
Aaron tells Richard he is quitting Gas Monkey just as Richard agrees to a drag strip showdown with Big Chief from Street Outlaws. The Monkeys are stuck to build a race car on their own at the same time he's challenged to his own race against another set of Outlaws.
Aaron struggles to get his BMW ready for the race with Street Outlaws. Meanwhile, Richard deals with the aftermath when his Challenger crashes on its final test run.
Richard and Aaron get together to look back at their partnership as Aaron prepares to say his final goodbye to Fast n' Loud.