Headache rack on a Mack

Usually they’ll sit right behind stacks and all fit in together.

 

Either remount the stacks to the headache rack or turn it into a weedburner.

 

Headache rack doesn’t mount to the back wall. Mounts to frame with u bolts. It can fit right behind stacks. I think it would look good too

 

OP said it would look strange leaving the stacks as is.
That left 2 options which i posted.
Also OP has stated in another thread he wants a as short as possible wheelbase.

 

I once had a '98 CH with a very similar exhaust layout. The boss offered to fabricate something using those vertical braces as part of the headache rack...we never did it though.
More recently, had an International 9900i purchased right off the lot. When the company made the deal, the negotiated price included a headache rack. That truck had stacks behind the cab, so the headache rack went behind everything. Didn't look too strange, but it was tough to see through the jailbars because they were so far away from the back window. Dealer did a nice job moving the catwalk back and everything, but I remember when I picked it up, they never moved the hook-up light from the cab. I asked the mechanic "what good is that?"...made him move it.
I had to replace the exhaust system once and it was pretty expensive. I was considering building a weedburner to get the headache rack closer to the cab so I could run more front overhang, but never got around to it...

 

If you just want a headache rack, you could try checking different manufacturers to see what might fit a Mack. If you're hung up on cabinets, that might be a different story...
Maybe just make it a "1 stack Mack" cuz there are a lot of those offset headache racks offered

 

They can customize anything you want. I did this on a cabnit I got a deal on to fit around my 1 stack international.

 

Its a 99 CH not a pinnacle but the rack is behind the stack. The hardware is there for the other stack also