Header fitment and exhaust routing with NP203

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75gmck25

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My ‘75 K25 has a TH350 and NP203, and I’ve got stock exhaust manifolds and dual exhaust. Space for the exhaust pipe is ample on the drivers, but really tight on the passenger side because of the shape of the crossmember braces for the NP203. I’ve got a 2 1/4” pipe fit through there, but with not much space around it.

If I switched to headers, are the exhaust pipes usually run under the the T-case crossmember or through it like I have them routed now? It seems that unless the collector is pointed in exactly the right direction to go through the space in the crossmember, routing could be a challenge.
 

CalSgt

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It’s pretty simple to route exhaust tubing where you want it, I personally wouldn’t run my exhaust below the crossmember unless I had to. I guess I haven’t done one with long tube headers, but I don’t see why it couldn’t be done with a few cuts and a “J” bend or two 45’s.

How far is it from the collector to the crossmember?

Here’s an example of what can be done with a “J” bend and two cuts.
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75gmck25

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I don’t know the clearance between the header collector and the cross member because I currently have stock exhaust manifolds.

I am looking for someone who has installed headers with an NP 203 to get an idea of how things line up with the passenger side crossmember. I can probably deal with minor misalignment using your suggestion, but the worst case is that the collector is too close to the crossmember to be able to reroute the exhaust pipe.
 

CalSgt

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I don’t know the clearance between the header collector and the cross member because I currently have stock exhaust manifolds.

I am looking for someone who has installed headers with an NP 203 to get an idea of how things line up with the passenger side crossmember. I can probably deal with minor misalignment using your suggestion, but the worst case is that the collector is too close to the crossmember to be able to reroute the exhaust pipe.
Where there’s a will there’s a way! Good luck
 

bucket

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My K30 has a TH400 and 203, along with headers and dual 3 inch pipes. It's tight, but it all fits above the crossmember.

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75gmck25

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That 2nd picture is exactly what I needed. It looks like there isn’t much room for any type of adapter (ball and socket, etc) on the end of the collector, but it does line the pipe up fairly well with the crossmember opening.
 

mcarlo86

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My K30 has a TH400 and 203, along with headers and dual 3 inch pipes. It's tight, but it all fits above the crossmember.

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Are you running the optional "part-time" 4x4 kit there?....no front drive shaft ;)
 

SquareRoot

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Hooker manifolds and a y-pipe.
 

DoubleDingo

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It’s pretty simple to route exhaust tubing where you want it, I personally wouldn’t run my exhaust below the crossmember unless I had to. I guess I haven’t done one with long tube headers, but I don’t see why it couldn’t be done with a few cuts and a “J” bend or two 45’s.

How far is it from the collector to the crossmember?

Here’s an example of what can be done with a “J” bend and two cuts.
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I dig your homemade "bandsaw"!
 

bucket

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CatRacer

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Here's what I did. Hedman headers and 3" true dual w/x-pipe. Mishimoto v-bands on the headers to 10" stainless flex pipe.
Obviously this pic was from construction and during mock up.
Sounds freaking awesome.
 

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