the blue one

im sure this is asked all the time, i couldnt find it, i searched, what size is my exhaust? im pretty sure i measured 2.25, but im not 100 % sure. i have an 88 305 tbi....muffler is cut off...going to justh ave cat and then run those fat tips out the back because they look bad ***, and need to know the size of pipe that would have gone to the muffler. anybody know it off the top of their head?