Instructions
Download and install the "San Andreas Mod Installer" (SAMI). It is available from such sites as filefront.com (see Resources).
Download the Ford Pinto mod of your choice.
Run SAMI.
Choose "Install a Mod" from the menu.
Click "Detect" to have SAMI locate your "Grand Theft Auto: San Andreas" directory.
Click "Browse" under "Mod Location" and locate the Pinto mod you downloaded. Double-click the mod zip file.
Choose "Continue" twice.
Type the name of the vehicle as you want it to appear in the game and select the car you would like the Pinto to replace.
Click "Install" twice. The Ford Pinto will now appear in your game.