'77 K20, California smog issue

[Action1081]

Hey everybody, square body newb here in north San Diego County, CA! This looks like a cool forum. Last year, I picked up a lifted '77 K10 shortbed from a guy who didn't know much about the truck's history. He got it from a friend (who had done a bunch of work to it in the past) and later decided he already had too much life going on to take on another project. I picked it up for pretty cheap knowing I was going to have to put some money into it and deal with the pesky CA smog test.

The truck was originally purchased in California and has been here ever since. The stock 400 engine was replaced with a 383 stroker, which runs nice. It has headers and a fairly new Edelbrock carb -- part of my smog issue. I am not 100% sure if the truck originally had a cat converter but my cursory research seems to indicate that it did. All of the original gauges (including fuel) have been replaced. I hear some of the heavier trucks from this era either didn't come with cats or if they did it may be easier to pass an emissions test. The inside of the driver's door says the GVWR is 6200. Sniffer test aside, there's no way it would pass a visual inspection with the aftermarket parts. The guy I bought it from probably had a buddy at a smog center who was willing to pass it.

I am looking for a decent wrench in Southern California who can talk to me about options. It may require putting original parts back on it to pass the visual inspection or I'll have to figure out something else. Pretty cool truck with a lot of potential but I don't have unlimited money to spend on it.

 

[Charlie]

 

[1973c10]

Welcome

 

[86 SCOTTSDALE]

 

[Craig 85]

I had a '77 K5 with a factory SBC400. I can't recall the GVW, but it had heavy duty emissions, ran on regular gas and did not have cat's. It had a smog pump, but I can't recall if it had an EGR. My last truck was a '79 K15. I had some issues when I went to sell it as it would no longer pass smog even though I hadn't changed anything. Turned out the intake was warped by the #8 cylinder. The Referee said I could change the intake to an aftermarket one, as long as it had all the emissions hook ups. I did not need an EO # on the intake to make it pass.

You can contact the Referee service, they should be able to tell you what you need. The number I had called 2 years ago was (800) 622-7733. The referee's name was Mike, he was based out of the El Cajon area at a Junior college. The local number he gave me was (619) 663-2074. Worth a try to see if he's still around.

 

[CSFJ]

You'll probably need to decode the vin to find out exactly what the truck started life as. They never made a 3/4 ton short box, so some parts have been swapped around. Unless I'm mistaken, the emissions testing facility will be looking for whatever equipment was installed on that vin.

 

[dvdswan]

Welcome to the site.

 

[Shorty81]

Welcome from the Buckeye State. Sorry about living on the left coast !!!

 

[skysurfer]

Do what Craig suggested, the 800 number he listed for the B.A.R is still valid. Without knowing what was oem for emissions you're going in blind and won't know where to begin until you talk to a referee.

 

[Action1081]

Awesome, thanks guys! Will definitely give the referee a call.

 

[Old77]

 

[Action1081]

Update...I contacted the B.A.R. and spoke to a referee (very helpful). We decoded the VIN and were then able to determine the emissions devices the truck had originally.

It is classified as "Heavy Duty Emission" since the GVWR is over 6,000 -- this means the truck did not come with a catalytic converter, EGR valve, or thermal spark control. The 400 CID engine came with the following emission control devices:

- positive crankcase ventilation
- thermostatic air cleaner
- thermal vacuum switch
- air injection reactor (California only requirement)
- throttle return control (California only requirement)
- evaporation control system (California only requirement)

I also found out the Edelbrock 1411 carb that is currently on the truck is not street legal in CA. The referee said the only carb that is legal in CA is the Edelbrock 1400.

Looks like I have some work to do to get this thing in compliance!

 

[DoubleDingo]

That's good you were able to talk to the referee. It being a heavier-duty truck helps you out a lot. It could be a nightmare if it needed all of the other crap that the lighter-duty trucks have. Hopefully you can find all that is needed to get it to pass and get it on the road.

 

[Craig 85]

Great news. This is the vacuum line diagram for a SBC 400 with California HD emissions. Figure 9 is w/o A/C, Figure 10 with A/C in the link.
https://www.autozone.com/repairguid...DIAGRAMS/VACUUM-DIAGRAMS/_/P-0996b43f80cb0d10

Non- A/C

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With A/C

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[Craig 85]

I'm guessing based on the description given, you need figure 10. The are a variety of terms used for the same parts listed. I'll try to simplify it for you and give you the part numbers I think they are.

- Thermal vacuum switch = Ported vacuum switch = Spark control switch (Napa #CRB 229205; ACDelco 212-351)

- Air injection reactor (California only requirement) = Smog pump and air injector tubes. You will need stock manifolds or headers with inserts for the air tubes.

- Throttle return control (California only requirement) = Control valve = Throttle return solenoid GM 1997479
(mounted on thermostat) Available from The Parts Place
Throttle lever actuator = Throttle Kicker = Return actuator (GM 17057174; Rochester 57174; ACDelco 214-1019; Carter-202-784)

- evaporation control system (California only requirement) = Canister