4020 Muffler Options

Hello, I hava '69 side console 4020 diesel that I need to replace the muffler. I want to put a larger body muffler like the 4230, 4230, 4050, etc. use. Will that style work with existing oval hole in hood and manifold? I do not want to make modification to either, but I would modify bottom of muffler if need be.

Thanks folks!

Jim
 
I have wondered about this myself, but have never done the research. A late 4020 and a 4230 use the same muffler. A 4050 uses the same as a 4430. Clearly the inlet is going to be bigger but I'm not sure about the radius of the muffler from the outlet. The inlet on the 4020 muffler is offset, but I don't think it is on a 4050.
Do you have a local JD dealer who would lay both out on the counter so you could compare them?
 
I have done what you want to do on my '71 4020. You need a 4240 muffler. The muffler is the same size oval as the original but is taller and has a larger outlet. The inlet pipe is not flanged but being the 4020 and 4240 use the same exhaust manifold all you need is the 4240 muffler clamp to hold it on. The muffler looks nice and any power increase will be small and noticeable only on hard pulls. Mike
 
I forgot to mention that you will need to cut off a small amount of the inlet pipe on the 4240 muffler. The inlet pipe is taller than the original. If you do not cut the pipe it can be seen at the bottom of the muffler oval when installed. Cut an inch or so off the bottom and deepen the linear cuts in the pipe. It will be a much nicer installation. Mike
 
I put a muffler from a IH with 3" in and outlet and it made a noticeable improvement in power. Being a 66 I have a round hole hood so you hopefully you can find a good oval alternative. The only change I had to do was use a standard exhaust clamp vs the 4020 clamp. I also used exhaust hedder heat wrap on the entire exhaust manifold to keep the heat down under the hood an not transfer to the intake manifold that is right by it. Over all I am very happy with how much better the tractor pulls and runs now with these changes.
 
I did something similar. I used a 4240 muffler on my 68. When I had the hood painted, I marked out a template and had a body shop cut and roll the oval shape into the hood. The outlet pipe on the 4240 muffler was still smaller than I wanted so I welded a larger pipe over that. Looks and sounds great. Much better than the puny-looking mufflers for the late model 4020s with their short oval body and thin little pipe.



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Newgen, that 4020 looks great. After I wrapped the manifold on mine to keep the heat in the exhaust not under the hood my muffler gets much hotter and most of the paint on the muffler is burnt off now.
 
Did you go directly to the SCV box or the (cut off) lever? The rockshaft should be easy enough to reroute the existing cable.
 

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