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Emissions requirements for a '79 in TX


Well-known member
Mar 20, 2001
Wichita, KS
Red on Red 1979 L-48
I just found out that I'm being transfered to the Dallas area in a few weeks. Does anybody know the emissions requirements for Texas?
Welcome 1979toy

...to the "me too" state of emissions controls. Seems that whatever California is implementing, the idiots over here want to do the same. :eyerole I live near Houston, where they are talking about lowering the speed limit to 55mph! :mad They refuse to realize that the smog limits have risen, because of the increased highway and road construction which leads to idling cars (i.e. more pollution). They are bowing down to the EPA's recommendation of lower speed limits or risk facing a hold on federal monies for interstate roadways. Am I the only one who thinks this is government sponsored blackmail? The EPA is claiming that they will enforce stricter penalties on industrial plants, but they can still get "emission credits." This means that if they can crush some old non-running cars sitting in a junkyard, they can pollute all they want. Damn burecrats! You can't live with them, but then you can't kill them, either. :L --Bullitt
The terms "blackmail" and "extortion" do not seem to apply when it's our government doing them. If you or I said "Give me a 28 percent cut of everything you make" that's extortion. If the government says the same thing we're supposed to be happy that they are taking care of us.
Thanks for the emissions information guys.
Anybody want to buy a non-emissions legal Corvette?
Probably the best thing to do is to make sure you live in an outlying county. Testing up there is only in Dallas and Tarrant counties. Just move out one or two counties, no testing. At least not for now, that could be changing in the next couple of years.

Funny you should mention that. Guess what! It changes May 1st 2002. All emmision counties AND surrounding counties are going to dyno testing emmisions. For 2003 all counties surrounding those counties go to it. All vehicles 1978 -1996 will have to be tested.
Now here comes a real kick in the.... The out of state forms to register your vehicle, green sheet, is going up in price from one dollar to.................$250.00 This is not a misprint!
If you need any help after you get to Dallas- you know where you can find me.
Stingray6974 said:
Funny you should mention that. Guess what! It changes May 1st 2002. All emmision counties AND surrounding counties are going to dyno testing emmisions. For 2003 all counties surrounding those counties go to it. All vehicles 1978 -1996 will have to be tested.

Do you have a reference/link for that. I would like to read the details. We do not have testing here in the Austin area yet but looks like it may be coming. Just would like to know what I am facing.

Unemployment doesn't sound too bad compared to what I will have to do to my Corvette.
You know what's amazing, though? The fact that some people in the EPA have for years been wanting to make it practically illegal for a person to drive an old car. Never mind the fact that the amount of old cars counts for less than a single percentage point, as daily drivers. They create laws that say that you must have emissions equipment regardless of your emissions levels. Hence, the underhood check. If your passing low emissions through your tailpipe (no jokes, please), why the hell should anyone care what is under the hood? I ask that anyone who lives in California, to please take part against senseless laws and lawmakers. Join SEMA, too. Reason being that whatever stems from the West Coast, usually ends up effecting everyone. --Bullitt
I get my info straight from the state rep. Dyno testing was supposed to start Jan. 1st but got pushed back until May 1st. There is a slight chance it may get pushed back again but not likely.
Shop owners have the option of purchasing a dyno or not. If they choose not to they will only be allowed to inspect 1996 and newer. It's called OBDII testing but are limited to 100 per month.
Cars that are 25 yrs and older are excempt from tailpipe testing but can only be inspected by a shop with a dyno. Jan 1st 2002 1977 will be excempt from tailpipe testing, 2003 1978 will be excempt, etc. However ALL cars must pass the safety( lights, wipers, brake test, horn, etc) and the visual emissions check (egr, pcv, A.I.R. pump, thermostatic air cleaner, etc.).
79TOY, although you have 2 yrs of testing left, the standards are quite easy to pass. I've been known to perform miracles:cool when it comes to emissions.
Also, in Texas, all vehicles 1983 and older are excempt from catalytic converters. 1984 and newer MUST have them.

I have an 81' and I'm located in Humble just north of Houston. I hadn't heard that pre-83 cars were exempt from cats. Where did you hear this? I guess this would mean that I could go with a dual cat setup on my car, and no one is going to fail me because I don't have the single cat setup?

Maybe you can help with this too: I currently have the computer LG4 carb, AIR diverter valve, distributor, etc. setup and want to remove them from the car, and go with an older setup. Will they check for the computer on my car? I'm hoping that I convert to a pre-81 emissions setup that will still functionally work, but clean-up the look under the hood. Ideally I'd like to trash it all, but I guess that's out the question. Seems like if you can pass emissions it shouldn't matter what's under the hood.
81 Vette,
The cat converter law is written in the inspection station guidebook. Every inspection must have one. A few years ago it was 80 and newer but was changed to 84 and newer. Cars requiring cats can have dual exhaust as long as they have dual cats.
The computer is not part of the inspection. Your can remove it as long as it will still pass the sniffer test. However you do have to keep the A.I.R. pump and lines on the car. They are part of the "visual" inspection.
Here's what you must have:
egr valve
pcv valve
vapor canister and all vac and vapor hoses hooked up
thermostatic air cleaner
A.I.R. pump and all lines and hoses hooked up
If you remove the computer you have change the carb and the distributor.
The surrounding counties around Houston will also be going to dyno testing in the next few years. Eventually it will be state wide.
Thanks for the help stingray6974.

Here's a more specific question on the visual (maybe too specific). My car has the the AIR lines routed to the headers and the converter. If I remove the AIR line routed to the converter by going to a pre-81 AIR setup that has only the tubes going to the headers.....is this something that they would be looking for on an 81' corvette? This may be to specific for you to have an answer, but I appreciate your help.
Talked to a local Corvette dealer (the one I just bought my '73 from) about this very topic. I plan to pull all the smog pump and emission crap off it. They said that anything pre '75 you can get away with it on, but anything else will require what it came with. Interestingly, he told me to keep my EGR, as I could encounter engine ping without it. Have you guys heard this? I have not had a problem with it on early Chevy engines in the past. I would like to know.
You have the three-way catalyst system with the Computer Command Control air management valve. Now I can't say to go ahead and rip that whole system out of it but if somehow by accident and older style (73-79 without the line going to the cat) just happened to end up on your car it would pass inspection without any problems. It must have a working system on the car but doesn't have to be of original design.
On your car and on 81vette's, is the emmisions decal beside the left hood latch. This tells the inspector what is to be on your car. If the sticker is not there or unreadable he will go to the C.A.S.S. book which will tell him that your car requires everything, even if it didn't come from the factory. If a corvette dealer told you that you can take everything off your car, he is wrong! By the way since I am familiar with all the vette dealers in D/FW I'm pretty sure I know who you are talking about.
As for the EGR valve not only must you have it, it will allow you to run more initial timing. At part throttle it lets exhaust gas (inert) into the cylinders which will lower cylinder temp, preventing pinging. At wide open throttle the additional fuel enrichment cools the cylinder. Is your vette a 4-speed or auto?
Emmision laws date back to the Clean Air Act of 1966 and mandated in 1968. However, as with 81vette, there are legal ways to re-interpet the law.
Stingray6974, I'd like to talk to you off line about that dealership. My '73 is an auto and the smog pump was not working when I got the car, nor did it have cat's on it and it was inspected, however, I am due very soon for a new one. Thanks for the info on the EGR, I will order a manifold with this option. I am still going to try to get away with removing the smog pump at a bare minimum, I hate that thing, looks like crap sittin on top ot the engine out front like that. Since I am sticking with a rebuild on my Q-jet (by the way, do you know anyone in Dallas that sells a rebuild kit for it?) then I think I will keep everything else relatively static until I drop in a new motor. Since I plan to go to headers very soon I need to remove the smog pump anyhow. I'll let everyone know if I get hasseled getting it inspected.

Would it help to put another emissions sticker from an earlier model onthe car, since this is what the inspector looks for? Can the stickers be purchased somewhere?

Do inspectors look for engine swaps like maybe a big block in place of the small block? As long as I kept the emissions equipment intact would they care? Do you have any idea what affect a bigger engine has on emissions, or is it more a function of cam overlap?
Better yet let's get together sometime. As for the carb kits there are only two brands to use. Dick Smith Auto parts carries the Delco kits. The other brand is Hygrade/Jiffy kit. Most parts stores will have it. Stay away from Neihoff and Tomco.

Big blocks and engine swaps are legal as long as you maintain the smog equipment. Hc is very sensative to cam proflies. Lobe seperation angle (LSA) needs to stay up in the 112 to 114 range to keep Hydrocarbons below 220ppm.

As of today dyno testing is still slated to start May 1st 2002. Also there will be a fifth gas tested - NOx. Aprrox. price of inspections 1978 - 1996 $40 - $45.

I picked up a Walker kit from O'Riley's the other day. I may check on Dick's (I assume you mean the one off Josey), the Delco kit may be better. However, I would guess that they are all about the same Delco - Jiffy. I also had O'Riley order me in an electric choke for it. I hope to do the rebuild, if I can get the garage cleaned out and some space on my work bench. I need to consolidate the parts from my '72 Cheyenne project. That one will end up going to my son at some point in the future now that I have the Vette. I ordered the Power Plus polished intake and the Ignitor II distributer converter kit as well. I want to get all this done by Christmas. I'm gettin tired of smelling like gas all the time just from driving the Vette.

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