Hi, everyone. Have a quick question about my 1985 D100 /6. I am looking to replace the current exhaust pipe from the original one with 2 cats to just a glasspack system with no cats. I have a few questions.

Question #1 is: What is the proper way to discontinue the hoses that come from the cat right below the manifold? One comes from above the cat and enters the bottom side of my intake tube and the other screws directly into the cat below the manifold and ties into a rubber hose and I have no idea where it goes. I am going to provide a picture of this at the bottom of the post. How can these be properly discontinued?

My second question is: Will discontinuing these systems effect the engine negatively in any way? Will it mess with the carb mixture once these parts are discontinued? I.e. turn my plugs black? Thanks for any help!

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2007 F-150 5.4L

1985 D100 225 Slant 6

The proper way is to leave it there. What you are proposing is illegal. It is a Federal crime (I know you live in Alabama where the people don't believe in things like science and global warming and their laws reflect it). It is against Federal law to modify or remove any of the emnissions components on a street driven vehicle. You can probably get away with removing the two cats and replacing them with a single high flow three way "California approved" catalytic converter. However, the cat won't live long behind a carb since carbs can't control the fuel mixture tight enough to avoid catalytic converter meltdown.




See my answer above. If that isn't good enough for you, get a factory service maual and learn about the system you are removing before you remove it.



Well, they could effect you negiatively in the form of a large fine (several thousand dollars), having shops refuse to work on your truck, and having your truck fail an inspection if it ever has to get one. Further, disconnecting things without knowing exactly what you are doing is always a bad idea.

Removing the catalytic converters and the air injection systems will not negatively affect your engine (it will negatively effect the emissions and the air you and your neighbors breathe), until the catalytic comnverter matrix melts down and clogs the exhaust system.

Yes, I am aware it is illegal. Me and thousands of other people everywhere as well who have done this exact thing. I'm not looking to do this just because I'm some kind of an inconsiderate redneck "science denier". The exhaust pipe is rotting on this truck and it's also leaking into the cab at the flange there where it bolts to the manifold and it's killing me with the fumes and I want to get rid of the old stuff and go back with brand new piping. Thanks for your reply.

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2007 F-150 5.4L



1985 D100 225 Slant 6

Then get brand new piping with a brand new "California Legal" three way catalytic convert WITH the air injection tube and duct the AIR injection line that currently goes to the cat into the new cat. Like THIS ONE.

The large foil hose the arrow in your picture is pointing to is part of the heated air intake and has nothing whatsoever to do with emissions or the air injection system or the catalytic converter. Leave it hooked up. And get a factory service manual so you can identify everything.

You can still get the aftermarket head pipe/pre cat (Dodge called it a "mini-ox") pipe that's on there now. Rock auto lists the DAVICO 59043 for about $170 plus shipping. Probably not super high quality. 1984, (83, in Cal.) on to 87 slant trucks used that with air injection. You can also get the center pipe/with main cat combo that hooks to that as DAVICO 54564.

https://www.rockauto.com/en/catalog/dodge,1985,d150+pickup,3.7l+225cid+l6,1084609,exhaust+&+emission,catalytic+converter,5808

I guess if you wanted to go with a no pre cat head pipe for a first gen Ram slant you'd have to have one fabbed up? I spent abut a year and a half looking for an obsolete Walker 44958 head pipe application for my '82 truck. That's a cat less head pipe with the air injection bung. There's seller on ebay that has one left right now ( I bought the other one). About double retail for what it sold for a few years a go when still available. Eye watering shipping. Only about 1 7/8 head pipe instead of the 2 1/4 my 2 bbl. should have OEM. That will also hook to the DAVICO 54564. Magnaflow seems to also have the center pipe and main cat as well at Summit. There are at least 3 different companies selling A body no air injection slant head pipes, but I doubt they will be usable on the 80's trucks? The one from TTI is 2 1/2 inch with a threaded bung for an O2 sensor. Maybe adaptable to an air pipe? Walker/Tenneco and Bosal have abandoned the slant truck applications for head pipes and cats.

https://www.ebay.com/itm/WALKER-44958-EXHAUST-PIPE-44958/401707174392?epid=76873812&hash=item5d879d09f8:g:mgcAAOSwvmxcxJzK&shqty=1&isGTR=1#shId

Waldron's exhaust has a kit for the muffler, rear pipe and tailpipe for '81 to '89 slant trucks in stainless or not. Walker still has all those parts for much less.

Hope you can do something about the leak. No Buena for sure. Reed's idea to run a regular head pipe to a quality Cal. approved cat with air injection provision would be nice, however you can do it. In Pa. anything newer than '74 has to have all the main emissions gear intact. I checked into many other northeast states, and nearly all ( including environmentally conscious states like Mass. and NJ, etc, exempt pre OBD vehicles ( '86?) completely or have a flat 25 year old exemption. PA. has some rural counties without emissions inspections, but made visual inspection for emissions gear part of the safety inspection. I recently learned that PA. is one of only 7 states left with safety inspections. Some years back we had safety inspections twice a year! A used PA. car, even with an expired inspection sticker brought a big premium at car auctions in the south. From anecdotal stories it sounds like there's a lot of Cal. cars that would have serious trouble with a safety inspection.

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1982 Dodge D150 ( Ram)
225 with A833OD. 2bbl. Non power brakes

Thanks, Hank. Down here in AL, we still don't have emissions testing. I will definitely be considering everything. I wouldn't mind doing what Reed said, but I'm just wondering how long a California cat would last on this thing. I know he mentioned the carb not measuring fuel properly, thus killing the cat early on. Might end up doing the original style cat. Whatever I do, I definitely have to do something before I die of carbon monoxide poisoning, lol. Thanks, again.

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2007 F-150 5.4L



1985 D100 225 Slant 6