Yes, you read that right. This tree hugging county in this tree hugging state requires that my 1968 F250, 2WD, 4 speed, Long Bed pass an emissions test before I can register it. It's a bone stock 360 with the factory 2 bbl and it blew 50% too much Hydrocarbons and 50% too much CO.
I'm not going to drop a smog pump or cat or any of that horsecrap on to it in order for it to pass so I'm wondering what is some low hanging fruit I can grab that will help me pass. I've got until Friday to bring it back without paying for another test.
Some background:
I've had the truck for about a year and a half and definitely smell it running rich when it's idling. Haven't done a compression test but I don't see any smoke coming out the exhaust. I live at 7500 feet and the testing place is probably around 6000 feet. I've got the Pertronix ignition kit for the distributor, factory coil.

My thoughts:
Could be jetted for sea level so maybe too much fuel for my elevation? I know that's an issue with my carbed Harley. Rejetting between sea level and my elevation makes a world of difference on the bike.
I've thought about removing the air cleaner and the PCV right before I retest in order to get more air into the mixture.
Would adjusting the mixture screws on the carb help?
Is there any secret sauce I can drop in the fuel tank to help?
Any other adjustments I can make that might help?
Hotter coil, hotter plugs?

Thanks in advance for your suggestions.

 

Carb rebuild kit with new power valve, reset float, jet down a size, make sure the choke opens up, and adjust the idle using the timing and the screws. Once you clean out the carb and make sure the butterflies and shaft aren't in a bind and are closing all the way, you can get it to idle off the idle circuit.

Clean oil that doesn't have fuel fumes in it can help, and the PCV working right. Unless you have terrible blow by, in which case you may want to rig the PCV for the test. Swerving suggestion.....

Hotter plugs, fuel additives etc aren't going to fix a pig rich mixture.

Once you get it registered will you be on an inspection schedule?

CA used to make you smog when you transferred, but if it was old enough, that was it. Now it's '76s and newer.... every two years and upon sale. It has to look OEM and pass the sniffer. Be sure you don't fail it on "inspection" by fooling with the air cleaner. If the carb is done right the aircleanier is fine--with a new or newer filter of course.

 

I noticed the idle was worse than 2500 RPM. So yes, adjust the idle mixture screws. Also check your timing to be at factory spec until it passes. The original carb tag number was C8TF-Y. The factory installed jets were part number C3GY9533C. These were stamped 54F. But this was for a new engine running the old style gasoline from back in the day. If you can't find the 54F jets, let me know. I may have some used ones.

 

Have you though of registering it as a collector car? No emissions tests. That's how I registered mine since the cutoff is 1975. There are mileage restrictions but they don't send inspectors out to check up on you..
It should run a bit better with a higher idle. At that altitude you can easily set the timing up for 12 to 15 degrees at idle with the vacuum line disconnected. If the carb is generic it may require turning the mixture screws in pretty far.to lean it out. Good luck.

 

Good tips! They will only give me "collector" status if I buy a 5 year registration. I don't plan on having the truck that long.

 

PA has historic / antique registrations. One time fee, good for life, no state inspections or emission test! Cost $81 + new title fee!

 

Just curious what they charge for that 5 year registration?
I guess we have it pretty good here in Ohio then. Historical plates are good for I think 30 years. No emissions test or inspection at all. Fee was under $100 and you can put old year-specific plates on...just need to carry the historical plate inside the vehicle. There are mileage restrictions but there is no enforcement.

 

the DMV lady couldn't give me an exact number but said the 5 year collectors registration would be about $500 but no emissions would be needed..
That's the reason I don't want to spend a ton of money on cats, smog pumps, EFI, etc. since I know $500 will solve my problem without any of that hooey.

 

My last five year registration was $213 and I don't think that there has been a significant increase since 2019. It is a 1970 F-250. You can bump the timing and turn in the idle screws and maybe it will pass. Can't hurt to try. You shouldn't need cats or efi to meet the 1968 standards if you have a good tune.

 

As much of a PITA as it can be, you WANT the engine to pass emissions. The standards are pretty lenient, so the fact that you arnt passing means the engine is horribly out of tune.

I'd start by tuning the carb. And making sure there are no vacuum leaks or misfires.

High Nox Is unburnt fuel. Usually from being too rich or too lean. Yes, too lean will cause that also.

The general rule of carb jetting is that you step down 1 or 2 sizes for every 1,000ft of elevation.

Also make sure that the ignition timing is correct. Advancing the timing a few degrees can help cut down on NOX By giving it a little more time to completely burn.

 

Garrett hit the nail on the head. You will be much happier with a properly running truck.

 

I would definitely like to get it running better. It's really a dog, given the fact that it's got 360 cubic inches. Plus, I get around 8 mpg. There is room for improvement.
What is a good source for jets for my 2100?

 

First things first, is general tune-up.

Old plugs, ratty wires, rotten vacuum lines, carburetor over 5-10 years.

Timing and carb settings need to be dialed in proper—about 15* BTDC, idle speed 600-850 RPM, and mix screws as lean as you can get before rpms drop.

get the engine is hot as possible before the test and put a little alcohol in the gas tank. With that said make sure you have a 192° or 195° thermostat if you have a 160 or something like that in there it’s going to run dirtier I’m not sure how pertronix performs, but I know that the Ford Dura spark one and two were designed and engineered to lower emissions, that’s why they went from points to electronic Duraspark I is one of the hottest forward ignitions they ever made in fact they made it for California in order to sneak by admissions requirements you can run spark plug gap‘s above .50 , you might want to look into that Run platinum spark plugs as well If you still can’t pass it you can install an EGR valve and spacer they’re still pretty easy to fine and they came stock on early 70s and up trucks and finally if you still can’t pass they do sell Chinese $35 generic catalytic converter‘s that you can just swap on for the test and then throw in the trash after.

Also, the thermostatic air cleaner should hooked up, they lower emissions too.

 

I aghree with all the above with one note. Don't set it TOO lean. This can cause a lean miss-fire. Which can raise the 2500 RPM test numbers even more.