New LS1 Owners - Newbie Tech - electric cut out, stock y pipe size?

Did a search and cant seem to find this, I want to put an electric cut out on my car and was wondering what the stouck y pipe size is so i know what size cut out i need, do i have to use the same size cutout or can i use bigger? thanks

I just used a 3" on my stock stuff

thats what i was thinking was 3"

im fairly sure the stock I pipe is 2.75"

Stock pipe is 2.75 but you can get a 3" cutout to work.

hmm mine was 2.75, but 3 will work