R model dual exhaust

[Coenut]

I am in the process of converting this truck to a dual exhaust.  Cab is a solid mount non airside. I measure the vertical stack mounts from the inside frame flange out on both sides.  Both are at 26 to center. Tacked the dr side on and have to pass side clamped. The drivers side is 1 inch closer to the cab than the pass side.  The cab mount that rests on the bar at the bar is 1 inch closer to the inner edge of the vert bracket than the pass side.  The hood and cab line up great. Should I be concerned or just move it 1 inch to match pass side.

[41chevy]

I  personally would split the difference and move the passenger side in 5/8 to 1/2 inch , You'll never see the difference if you split it. I think the stacks look better tucked close to the cab.   Paul

[Coenut]

That's what I ended up doing.  I got a little nervous because there is more cab overhang off the frame to the drivers side than it does the passenger side.   The center of the cab at the rear window is dead center in the frame.  Are the r cabs wider to one side to accommodate the driver.

[41chevy]

 

1 hour ago, Coenut said:

That's what I ended up doing.  I got a little nervous because there is more cab overhang off the frame to the drivers side than it does the passenger side.   The center of the cab at the rear window is dead center in the frame.  Are the r cabs wider to one side to accommodate the driver.

I really don't know, all the ones I've worked on or seen never had duals so never an issue. I'll have to look close at mine when I get to Va next thursday.    Paul

[kscarbel2]

COEs aside, the dual exhaust piping (routing) on a Super-Liner or Value-Liner is a straightforward affair, with the piping efficiently and effortlessly passing under the cab to the rear.

However, the east coast R-model of course, with the low cab mounting, results in a convoluted exhaust piping arrangement, so much so that it's arguable to avoid having it.

[Coenut]

This was a lot of work to make this look correct. To get the y pipe in the right location.  I had to slide a crossmember back 3 inches or so to the next set of holes drilled in the frame.  Luckily that was fairly straight forward but then I had to fabricate new fuel tank frame mount brackets.  To someone not familiar or knowledgeable with Macks it looks like it's factory.

[ranchhopper]

Bolted my dual exhaust right to the cab since its a solid mount cab anyways cant see the other stack its hidden by the horn stanchion.