The Magnum Opus is a customisable vehicle created by Chumbucket with the help of Max Rockatansky. Chumbucket led Max to the vehicle after Max's V8 Interceptor was stolen by Scabrous Scrotus. Chumbucket showed Max the plans for upgrading the Magnum Opus, as well as how he plans to replace the V6 engine with a V8 to give it more power.
With Chumbucket's help, Max upgrades the Magnum Opus to be better for the challenges ahead and to surpass the interceptor.
Along the way, Max helps out certain characters by clearinwho help him progress in boosting the capabilities of the Magnum Opus in exchange for removing the threats and presence of other factions in the areas.
Eventually with the help of Chumbucket, Max finds a V8 engine to fit the Magnum Opus so that it would be equal in terms with the Interceptor. After the Magnum Opus has been upgraded significantly, Max tracks down Scabrous and takes out his war party, this battle leaves Scabrous on the edge of a cliff awaiting one more push to send him and his vehicle off the cliff.
Chumbucket realises this and clings onto the front of the car, attempting to persuade Max to leave the Magnum Opus behind as to not ruin his dream and work. Max decides against Chumbuckets pleas, using the Magnum Opus to give Scabrous' vehicle over the edge, along with the Magnum Opus. Max furiously rams the Magnum Opus into Scabrous's vehicle to send it over as Max jumps out of the car to save himself.
The Magnum Opus along with Chumbucket are destroyed in the collision, bringing an end to a car that had surpassed the interceptor.
The Magnum Opus is unique in the sense of being the only car that Chumbucket rides with Max and having unique weapons, such as the Harpoon, Thunderpoon and Sniper Rifle.
The car has six potential bodies, some of which, like other vehicles in the game, are based on vehicles from Mad Max: Fury Road:
- Death Rattle - Based on a 1934 Chevrolet Master 5 Window Coupe
- Die Rolla - Based on 1960s Rolls-Royce
- Wild Hunt - Based on a Ford Falcon, similar to Max's own Interceptor
- Shovelface - Based on a 1968 Ford Mustang Fastback
- Furnace - Based on a Perentti Coupe, an Australian kit-car based on the chassis of a Chevrolet C3 Corvette
- Ripper (DLC) - Based on a 1960s Pontiac GTO