Does anyone know if a 1981 F150 5.9L came with a factory catalytic converter?

 

It probably did, but here are several ways to verify it had one. Look at the fuel gauge. Does it say "Unleaded Fuel Only". Open the fuel door on the side. Does it say "Unleaded Fuel Only" on the back side of the door or on the cap? Lift the hood and look at the sticker on the radiator support that has the diagram and info on it. Does it say "Catalyst" on it. All these are clues that it did have a cat converter on it.

 

If it did and you do not have to do Vehicle Emissions Testing I wouldn't worry about putting one back on. I am pretty sure everything had a cat on it after the mid 70 or somewhere around there.

 

I didn't know that everything that was "unleaded fuel only" had a cat converter. Knew that the lead was not good for the cats but thought the unleaded fuel only preceded cats to reduce lead in the environment. That makes it easy to know. My '75 Ford pickup was unleaded only but back in those days people knocked out the restriction in the filler and bought less expensive Regular gas.

NC doesn't require emissions tests for pre-OBD II vehicles but its illegal to remove emissions equipment. Not sure if the exhaust shop will do a system without cats. I'll find out. Thanks for info.

 

Exhaust shops in my area won't.

The lead in the fuel ruins the cat converter, that's why you can't run the leaded fuel if you have a cat. The cat convertors really started on most vehicles in 1975, but as a little trick, Ford came out with the "F150" and upped the GVWR a little bit, so some of the trucks still did not have cats. I believe later the gov upped the GVWR rule, and that included most all the pickups except the very heaviest GVWR rated trucks. In the 80's you will still find some of the larger f350's with 460's in them, and they will be "non-catalyst" on the sticker. There was a thread on here in the past week that someone had some pictures in, and you could see "non-catalyst" on the valve cover sticker.

They then upped it again to include most all trucks except the diesels, and then they included them also, so the diesels started having converters and egr's. There is a big deal in California now, they have included the big rigs, and there is a big stink about it and some transport companies may be moving out of California, they can't afford to upgrade their fleet to meet the standards.