To find the exact towing capacity for *your* specific truck, you need to:
* Check the sticker: Look for the sticker on the driver's side doorjamb. This sticker lists the truck's specifications, including the maximum towing capacity.
* Consult the owner's manual: Your owner's manual will also specify the towing capacity based on your truck's configuration.
Without knowing the specific engine, transmission, and axle ratio of your 2005 Silverado 1500 regular cab, any number I provide would be unreliable and potentially dangerous.