i need to know quick, if the original muffler, is 3 inch coming in or 2.5, im not worried about the tail pipes, but i have all original pipes, and im putting flowmaster on and i need to know this before hand, thanx!

 

I believe that stock LT1's had a 2.75" intermediate pipe going into the muffler. I'm not 100% sure, but that number stands out for some reason.

 

well i was just doing a little more research on it, and the pipe itself is 2.75, but when it goes into the muffler, it is 2.5

 

 

If I remember correctly I also think the original STOCK intermediate pipe is 2.75" where it goes into the muffler???