i have flowmasters 40 series on my truck right now...is it possible to add another 40 series to make it true dual..also i have turndowns...thanks for ur input...

 

I bet its possible, I doubt you can just add another one, they would probably cut the old one off to get rid of the "y" pipe up front. I would think you could reuse it maybe. I have that exact setup your talkin about though true dual 40 series dumped w/ turn downs and love it!

 

So you have the true dual piping but its y piped into 1 muffler? hmmm... I'm not too familiar with that, but if you provide a muffler they should do it, all they have to do is cut the muffler from the y pipe, and the y pipe from the pipes, run the pipes & place the mufflers & had a turn down to the new muffler.