Before getting started with this cheat you’ll need a some cash on hand, a cooperative online counterpart and private lobby.
1) Buy a 1969 Chevrolet Camaro Z28.
2) Buy every engine available for that car.
3) Buy every part for every engine including every aspiration part.
4) Back out to the main menu so it will the engines and parts you purchased.
5) Head back to the engine purchase menu and sell every engine (DO NOT LEAVE THE ENGINE MENU).
6) Press your Xbox 360 button and join your friend’s lobby.
7) Leave the lobby and quickly press B to back out to the title screen (the screen that says ’Press A to Start’).
8) Go back to your engine purchase menu and you will still own all the engines and parts.
9) Repeat steps 5-8 for infinite engines you can sell for infinite cash.