I just got done putting dual 4" on my truck. We went from the downpipe w/ a 3.5"-4" reducer then a 4"-5" reducer. Then 3' of 5" pipe was laid and made a 4" y to connect to that. Then we ran 2 4" pipes straight out the back.
Sounds great. I will post some pics of it when we get the tips in. It is alittle crude but from the side and behind it looks good.

This is great but...

:nopics:

This is great but...

:nopics:





i know, i know
But right know it looks kinda odd without any tips.
I will try to get a picture of it today and post it.

here is a crude photo of 4" duals. More to come.

:cool2: