'86 F150 4.9L 4 WD. My truck has 2 cats on it. I'm looking at replacing the exhaust, and was wondering if there was 1 cat that will replace the 2 cats that I currently have.

Thanks.

 

I'm not 100% certain on this, but I believe that there is only 1 true "cat", the other is a resonator. I could be wrong, and have been before, but hopefully someone that knows more about the exhaust will jump in and clear it up for you. No need for cats here, so it is common for us kids to cut 'em out and make it loud.

 

I don't know about the 300 but both of my cat's are the same, one behind each header.

 

Their inline single exhaust.

 

These trucks are getting older, and so is the technology they were built with. I think you would be fine to replace the 2 old and worn out cats with a brand new cat.

 

Mine is the same way, 2 cats inline on one exhaust pipe. I also thought one of them might actually be a resonator, but I don't know the answer. The air pump pipe only goes to one of them (the second one).

 

My 86 F150 only had one cat on it's factory exhaust.

 

My 86 has none and most of the exhaust is still original. The dual cats were - front - reducing catalyst, works in absence of O2, - rear - oxidizing catalyst, works with an excess of O2. The pipe is there to provide the O2 needed for the rear cat. Newer cats are dual bed in one shell, just have an air pipe in the middle.

 

As was mentioned earlier, these trucks are older and in the day these trucks were made, technology wasn't as advanced. Now days you can get both of these converters, in one universal unit. The single functions of both the older type catalytic converters combined into one unit. If you live in California, make sure that it is 50 state legal, as even if the part works, and will pass smog with it, it has to have a CA. BAR number to make it legal here.

 

So do the newer aftermarket cats have a fitting to connect to the stock air injection pipe?

 

Actually, after I asked I went looking and LMC has this part, with the air pipe on it. But its not legal in California...

LMC Truck Parts - Page 46

 

What I find weird is, the air pump pipe is between the cats, just behind the first one.

 

I'm no expert, either, but from what I have read, back in the day, the cats were not as efficient so they installed two in line, and to provide enough oxygen for the second cat to work efficiently hooked it to the airtube. Now, the technology is so much more advanced, only a single cat is necessary. If you try to replace it with a 50 state legal system, they will still have two cats. If you go 49 state legal, you can go with a universal cat from a number of manufacturers.

A lot will depend on what your future plans for the truck are. Even if you aren't required to have emissions testing by your state or locality, I believe cats are still required by federal law. A good free flowing universal cat is not expensive or difficult to install.

Ron

 

No, the newer cats have both of the older functions in one housing.

If you read post #8 and #9 this will explain how they function.

You can buy a universal fit cat for California vehicles, but they MUST have a CA BAR number to be legal. If it does not have the number, then it's not legal. This goes to ALL aftermarket parts related to smog that isn't exactly like it was from the factory. Aftermarket "Exact fit" parts that look and function like the originals excluded.


It's that way with the newer single cats too. The primary and secondary cat functions is in one housing on the universal fit one, therefore the air pipe is in the center of the cat.

 

Got the new exhaust from Summit Racing today, Looks impressive. going from 2.25 to 3 inch pipe.