Won't pass emissions no matter what I do

I have a b2000 that refuses to pass emissions no matter what I do to it. The HC and CO were too high on the high idle test. On the low idle they passed. They don't test for NOX so I don't have to worry about that. The CO was pretty high but the HC was about 8 times the limit. It was 8.32 and the limit is 1.2.
What I've done to the truck so far:
All new exhaust header back with a new cat conv and pacesetter header, weber 32/36 dgev carb, spark plugs, ngk wires, accel ignition coil, dist cap and rotor, fuel filter, pcv valve, breather filter, thermostat, oxygen sensor, coolant temp sensor, cleaned out the egr valve, timing belt, tensioner, water pump, head gasket, intake man gasket, fresh coolant and oil change.
And when I do the tests I run premium gas. Last time I retarded the ign timing and leaned the mixture on the carb.
Is there a way to cheat the test to help me pass?

With a Weber carb, you don't get any signal from the oxygen sensor or coolant temperature sensor (unless you're talkin' about the gauge sending unit near the thermostat).

Sounds like you need to adjust and/or re-jet your carb. I'd say a repair shop with an exhaust analyzer should be your next step. And an old guy there who's actually seen a carburetor before....

Chances are you aren't going to pass with a 32/36 carb and a pacesetter. As Cusser said there is no O2 sensor input so it can't lean out the engine on demand.

Read your testing program to see if it has a "loophole". Here they can't make you spend more that $250 to fix a problem.

Here is a great resource for tracking down the problem which I think is the O2 sensor not working.

Probably not. But because they don't test for NOX you can advance the timing to light off the mixture sooner and give the engine more time to scavenge the mix. If you can find someone with an exhaust analyzer you might be able to get your numbers down just by adjusting timing. It wasn't clear what temperature your thermostat is but a 195 degree unit might help. The converter has to be hot to do its job properly, so running the engine at a fast (2500) idle just before testing might also help bring your HC numbers down. The converters' job is to recombine the HC and CO into H2O and C02. The trucks originally come with 2 converters and you have removed the primary unit and the downstream unit may not be getting hot enough to light off the chemical reaction.

The other problem you are going to face it that there is no longer any air injection system in place and that is where extra air (oxygen) was supposed to be introduced from to help the converter do its job.

Part of the problem is that the header is shedding heat, not fully heating the cat. I had a B2200 a while back and I had to put 2 aftermarket cats in, back to back to get it to pass.

That being said, you probably ned to jet the carb smaller to get the CO down.

Would it help if I heat wrapped the header and added another cat?

First address your HC issue! Your carburetor is dumping way too much fuel in to your engine.
Once you fix that, your CO will almost disappear.
Have you replaced the air filter???

Premium gas doesn't burn any better. Stop wasting money on it.
Higher octane only resists pre-ignition better.

Yes, you can get the cat to light better if you wrap the header - and YES you need to re-jet that carb.

If the CO (and HC) are so high that you fail the test, then it is way too rich even for making peak HP. You will almost always find that a vehicle that fails emissions will run so much better once you make it pass - that is part of the idea after all

Maybe the vacuum diaphragm is perforated on the distributor and if that is the case, timing will stay retarded in relation to engine speed. NAPA sells replacement diaphragms in their "Standard" (ECHELIN) line of parts, but you are probably going to have a hard time if the parts people don't know how to use the paper catalogs.

I heard about a guy who had trouble passing an emission test and it turned out the brake booster vacuum line was dry rotted, allowing too much air in under the carburetor. Just something else to check.