i need some advice with installing a stack in my truck.
im low on budget so i decided to do all the work my self. so far this is what i have, a 6" pipe off my semi with a 5" adapter on the bottom of it, and i cut off the muffler from my truck.

so my question is, could or should i put a 4" adapter on the cat. converter with a piece of flexible tube on it with a 4" into 5" adapter on the other end that connects to the stack?

or can i cut off the cat. and do a 3" into 4" adapter with the flexible tube connected to a 4" into 5"adapter connected to the stack?

any advice or recommendations would help thanks

 

Sounds neat, I'll be sure to watch for answers too. Sorry I can't specifically help at this time.

 

I would cut the cat off and do it with as least flex pipe as you can, but leave a small length somewhere for flex IMO. I had a bunch a flex under mine at one time and it blew off and moved around too much. Now I have it solid the whole way with about a foot of flex off the downpipe so it has some give. Works a lot better. As far as the 3 to 4 and 4 to 5 you can pretty much do that where ever, how ever.

 

cool thanks for the help. all i have to do now is buy the stuff. im probably going to do it this weekend

 

You bet, let us all know how it turns out

 

in my case i couldnt get flex to bend sharp enough to look good coming up through the bed. its easier to buy a 90 degree piece to use there