Pipe routing with full size headers

[Mastiff]

I know there are threads on this but I haven't seen quite what I'm after. The deal is that the crossover pipe is interfering with the driveshaft in front. I see how people route close to the trans pan, but with the headers they come down past that. The flange on the passenger side is right next to the shackle hanger (impossible to install new bushings in one piece). I'm also not interested in trying to go above the crossmember on passenger side because all my fuel lines are going right there. Best I can think of is to snug the crossover as close as possible to the front of the crossmember, like within an inch, so the shaft could easily go over all the time. Is that reasonable? Any other clever ideas?

 

[tRustyK5]

With full length headers I'd run dual to behind the T-case, crossover there and then finish.

As for shackle interference, BTDT, so this time I went with Hedman Elite's. Yiou can see they tuck up a fair bit higher and the shackle area is clear now.

I went dual, but where my balance tube is is where I'd do the crossover if I was going single. It ends up a little back of the rear output where the rear shaft doesn't have much up and down range.

 

[Mastiff]

With full length headers I'd run dual to behind the T-case, crossover there and then finish.

How does the pass side pipe get past the crossmember? It's tight with the tcase there, and I've got all my fuel lines and filter on the frame right there too.

Good looking setup BTW. Any pics installed?

 

[tRustyK5]

Exhaust pics are always tough, so nothing much better than what I posted. With the Hedman Elites, even 3" is a straight shot past everything on the passenger side. The driver's side I did remove the auto trans shift linkage as it was worn beyond belief anyways. Went with cable shifted floor shifter, and it made the exhaust easier.

Mine is a '90 Blazer, TBI, 700R-4, 241 for reference.

 

[dyeager535]

The Hedman Elites as shown probably will give you more options. Further forward and higher gives more options on where to crossover.

I've contemplated the same issue, but I think with the headers pictured, even getting the crossover under the front output shaft might be do-able?

2.5" is likely more than enough diameter for half of a 350. 2.25" may be enough as well, but FWIW, a 1 5/8" primary supports 203CFM, so even with 2.5" collectors, flow potential is far less than the sum of the primaries. Even if a 3" collector, still less than what the primaries support, but the manufacturers must have some understanding of the forces at work here, so their sizing is probably a decent baseline.

If I could find even a rough formula that would allow one to figure volume of the exhaust based on heat shedding, that would allow a decent guesstimate of how small you could go on a crossover.

 

[Blue85]

This is a challenge, especially if you have a lot of suspension travel. There was somebody on here who turned the PS exhaust around forward and ran the crossover in front of the oil pan.

Mine was full dual, but I converted to a dual inlet muffler when I did the anti-wrap bar. You could do the same thing with a Y-connector though. The tightest spot is between the T-case and the frame rail.

 

[Mastiff]

I ended up just doing my original idea and snugging it up close to the crossmember. I don't think my suspension can droop enough to hit it. Duals all the way would be slick, but I have rubber fuel line in the way of getting over the passenger side crossmember right now.

 

[dyeager535]

Looks good to me!

Did you merge the two just out of sight in the picture? What size pipe?

 

[Mastiff]

Yeah, there's a Y then into the muffler just out of the pic. 3" pipe I believe.