Help me build an exhaust

Dont give up your storage, being a flatbed operator thats most important. Im a little late to the party but I can help you build a stack system to go with the headache rack. I’ll need the style of headache rack you wanna use, the clearance you have to run exh pipe over the frame and under the cab. Take this measurement with the air bags on the cab deflated, the size of stacks you wanna use and then lastly I cant remember if you’re going to leave your cab farings on or not. If leaving them on I’ll need to know the distance between them as to weather or not the stacks can go on the side or back of your headache rack.

 

Another option would be an offset cabinet rack with room for your stack alongside it on the passenger side.

 

I'll see if I can dig them out. I haven't seen them in 30+ years,but I definitely didn't toss them.

 

So this is what I would build. Looks like your headache rack will have 7” of clearance from the back of the rack to the front of the uprights. So with that I would mount it 2” from the cab giving you 9” of clearance for the stacks. So using 7” stacks that gives you an inch of clearance between the rack/stack and stack/cab. Using Lincoln Chromes catalog, https://d9hjv462jiw15.cloudfront.net/media/329108_lc-catalog-2017.pdf , I picked out the slim Peterbilt clamp PN: 45-00073 qty of 2 for mounting the top of the stack to the top of the cabinet and wide Peterbilt clamp PN: 50-00073 qty of 2 for mounting the bottom of the stack and the elbow to the bottom of the cabinet. I would use their universal 90* elbow with the 20 top/bottom leg as your cabinet looks to be about 17” above the frame so this should put the top of the pipe just underneath the cab. That is PN: L90007-E20-B20-1103 qty of 2. I choose the short 30 or western star style type of curved top stack PN: 507A-96-1103. This is an 8’ stack and should sit right around 12’6-13’ at the tip based off measurements of my frame height. I went with Lincoln Chrome on my truck because they where the only ones to offer a single piece pipe this long. Dynaflex stacks are a 2 piece design. The part numbers will change based on the pipe size so you’ll have to look at the catalog to see what size you want along with the cut of the top of the stack.

Now for the stuff underneath Im guessing you got 5” there now so it should work to put 5” back in there. I tried finding my old go to company for exh but cant find them so I went off to amazon. Found a place called Heavy duty Manufacturing. They have a Y-pipe PN: 14-500A qty of 1 90* elbow PN: 12-500FA qty of 2 and clamp PN: 20-500ES qty of like 8. You’ll need some 5” pipe to lineup the 5” elbows to the stack elbows from the Y-pipe and then I would do a short section of flex pipe from the elbow to the stack elbow just to allow for frame flex and all. Its kinda hard to picture it all over the internet with out drawings but I think I’ve painted an ok picture of what I think would look pretty decent and how I would lay my truck out if I was doing what you’re doing.

 

Check out the newer trucks with the stacks behind the cab. With the DPF’s mounted to the frame there isnt the need to hold a lot of weight anymore, when running vertical exh.

 

The Peterbilt clamps are like 4” wide so you could get some 4” or 6” by 1/8” thick aluminum C channel thats like 8’ long bolt it to the frame with 4 bolts, then have a flat plate welded into the channel to mount the clamps to, then make some cross braces out of angle in an X pattern from the top of the channel down to just above the frame. That should be sturdy enough to hold the pipes tell you do the headache rack.