I've looked around read forums and done research.but didn't get answer.So here we go . I was wondering is my factory single pipe 3" or 2.5 ok with that being said guys with the borla 40085 are yall using the one borla and then using a y pipe to dual out or are yall going single pipe to y then two borla mufflers to dual pipes. I know I'm probably overthinking it . Also did muffler shop provide the aftermarket y pipe. By the way it's a 4.6 3v. Thanks in advance .

 

Your exhaust is neither 3" or 2.5", it is 2.75" from the Y pipe. The Borla #40085 is 3" in/out, and your exhaust shop can flare the piping 1/8th inch all around for the muffler to fit onto the intermediate pipe, and they can make the muffler mate to the tailpipe with added pipe in the same fashion.

For dual tails, yes Y piping after the muffler achieved this easily. Have a look at my setup.
https://www.f150online.com/forums/sh...&postcount=213

 

Thanks man how much did everything cost when u were done

 

Fab/install was $230.00, parts I provided was $254 and change.