To find the exact dimensions for your specific Silverado, you'll need to:
* Check your owner's manual: This is the most reliable source.
* Look up your specific year and model on a parts website: Sites that sell replacement glass (like auto glass retailers) often list the dimensions in their specifications.
* Measure it yourself: This is the most direct but possibly least accurate method, as you'll have to account for the frame's thickness.
Without knowing the specific year and model of your Silverado, I cannot provide the dimensions.