how thick is the stock exhaust on an LT1?

 

thick?

do you mean the thickness of the exhaust manifolds or the thickness of the y pipe and system behind it?

Just curious, I never heard anyone ask about the thickness of an exhaust although many years ago some of that flexible exhaust pipe was so stinking thin it would last barely a year around salty new england roads.

 

my bad, how wide is the pipe after the y pipe. im going to make exhaust flanges and i need to know what size hole saw i need.

 

stock is 2.5 inches

 

I could be wrong but I thought that pipe is 2.75" from the factory.

 

No, it's 2.5" back to the muffler and then each outlet of the muffler is 2".