This one ended up being kind of a bummer. From the moment I drove the RV up the first hill after buying it, something blew out and the exhaust got much loader. I replaced the exhaust manifold gaskets, no change. I installed special torque holding exhaust manifold bots, no change. I was sure the OEM cast iron exhaust manifolds must be cracked so I ordered a set of headers.

And not just any headers, Doug's Headers, which I believe are also known as Thorely headers. This things are very nice, great volume, and are ceramic coated. This is some of the nicest exhaust bits I have had on any of my vehicles.

Getting these headers installed required me to develop some new skills and buy some new tools. I now had a pipe expander and I love it. I can also effectively MIG weld exhaust pipe. Normally you would use TIG, but I don't have a TIG welder and even if I went out and bought one, I have much more practice with MIG. I am happy to report, the welds that I made don't leak at all.

Even though these headers look great, the bummer is that the exhaust noise is unchanged. There is still very audible exhaust blowby happening somewhere. My new theory is that the right head gasket is allowing exhaust gas to escape underneath the intake manifold. What I don't understand is that the compression test came back okay. The sound is clearly louder above the engine than to the side of it, and the noise is clearly coming from the right side and not the left.

I sprayed everything down with soapy water looking for exhaust leaks. There are no leaks where the headers attach to the heads, and there are no leaks at my weld joints. There are some minor leaks where the header collectors join up to the rest of the exhaust with a joint, and there are some leaks where the pipe enters the muffler. Both of those could probably be resolved without too much issue (muffers just need clamps) but neither of these is the source of the exhaust noise so I am putting them on the back burner for now.

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Smll Med Lrg	Smll Med Lrg I love this thing. The pipe expander works with an impact wrench and works very quickly	Smll Med Lrg	Smll Med Lrg
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Smll Med Lrg Its not ideal that the exhaust shrinks down 1/4" here but I wanted to keep my original muffers	Smll Med Lrg	Smll Med Lrg	Smll Med Lrg
Smll Med Lrg Just keep welding in small sections all the way around	Smll Med Lrg in the end the entire pipe is welded	Smll Med Lrg from inside the pipe you can see good (but not perfect) weld penetration	Smll Med Lrg headers have a O2 sensor bung that I will use eventually, for now they get plugged
Smll Med Lrg	Smll Med Lrg not the prettiest weld joint, but it functions without leaks	Smll Med Lrg	Smll Med Lrg
Smll Med Lrg	Smll Med Lrg	Smll Med Lrg had to clean up some metal shard across the threads	Smll Med Lrg
Smll Med Lrg	Smll Med Lrg	Smll Med Lrg the transmission lines come very close to the headers and need to be rerouted	Smll Med Lrg for now, I pulled them away from the header but long term I need to make new tranny oil lines
Smll Med Lrg	Smll Med Lrg the cold air inlet of the hot air choke system is super loose, I just pushed it back in	Smll Med Lrg	Smll Med Lrg
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