What is the stock exhaust pipe size on a 1998 silverado?

The stock exhaust pipe size on a 1998 Chevrolet Silverado varies depending on the engine. There's no single answer. You'll need to specify the engine size (e.g., 4.3L, 4.8L, 5.7L, etc.) to get an accurate answer. Even then, there might be slight variations depending on the specific trim level.

To find the exact size, it's best to:

* Check your owner's manual: This is the most reliable source.

* Measure the pipe diameter yourself: Use a ruler or caliper to measure the inside diameter of the pipe. Do this at a point where the pipe is straight and not tapered.

* Consult a parts store: Provide them with your truck's VIN and they can look up the specifications.

Without knowing the engine, any size given would be just a guess.