OK here is my problem. My stacks are 6" miter with the bottom being 6" id. So do I use a 6" od pipe out of my cross over box. That will overlap about 2 inches. Or throw on a reducer and run a 5" pipe half way up inside the stack. Which will be stronger.

 

Anybody ???

 

show me exactly what you have, so I can see. right now I'd say to butt them together and then use a piece of 6'' to overlap both and then weld 'em up. If you can, do it so the heat box hides it.

 

my thought is if i run the 5 inside the stack it will be stronger than clamping the top 2 inches of the 6 inch. The heat box is 6x6 then either the 5 or 6 inch pipe up 10 inches. Then mount the stacks.

 

Do you have a welder?? Or access to one?? You really don't want to run down to a 5'', the 6'' will be real sloppy going to a 5''.

Also, you don't want to use clamps while butting together. You'll take a chance of loosing them going down the road. Unless you use a clamp higher up and attach to the bed rail.

 

the stack will fit over the the 6 inch pipe. then clamp the 2 of them together. yes I have a welder and a plasma cutter. How do you mean sloppy. By looks or what??

 

Bad choice of words (sloppy). I have 6'' aussies coming from 5'', but you're already 6''.

Here's what I'd do then, I'd flare out the 6'' stack with a ball peen hammer and put it on then weld it up. This is better than going down to 5'' reducer.

It be better if you could post some pix so I could see your exh. box, set up. PM me with an email and then we could work it out.