I have a '84 Iroc-Z with a 350 carbed in it right now. The motor is brand new, it has roughly 10k miles on it. However, the original motor was a 5.0L which I think was EFI. Anyways, I have numerous exhaust leaks in my cat-back right now, actually its leaking all the way from the header-back in various sections.

Is there a cheap way to fix this myself? And lastly, does anybody have any other neat tricks to passing emissions? I've heard adding methyl hydrate is a good helper.

Detune the crap out of it. Run it at about 2000 rpm with the hood up in the parking lot before the test.

As for fixing the leaks, you can get this white stuff in a tube at the parts store that is meant for fixing cracks and sealing joints. It wont last too long, but if you slather some over where it is leaking...

If its Carbed, i was told you can put a small amount of water down the carb before you go to get it tested. But I'm not sure how much of a difference it would make or not cause im efi..

pull the timing back, mine passed with flying colors after doing that.

I can't tell where you're from, and you didn't say what kind of testing they do. I can say from what they do here that if you have exhaust leaks, they won't even test you and tell you to come back when they're fixed. So, let's assume that and go from there. Is there a cheap way to fix this yourself? No. You need to replace the bad piping. The "easiest" way to fix it is to install emissions-legal headers (Hooker 2055HKR would be my recommendation), a cat for the '86-'90 TPI single cat application, and a cat-back for the same application. The A.I.R. fitting will require some fabrication because the driver's side fitting faces to the rear on the 2055's, but to the front on your original system. No biggie, but something that has to be handled. This should fly through emissions inspection with the possible exception of California, which if that's where you live, you're at the mercy of the inspector. The other possibility is to get Edelbrock TES headers, cat & cat-back for the L69 application. This will also require an L69 EFE valve, but otherwise will all bolt up and meet emissions requirements. The final choice is to replace all of the exhaust with factory-like replacement parts, which will probably cost as much as the headers and complete system above, and will definately be lower performing, especially for a 350.

Now, we really need to know what kind of carb you have. For the record, there were no EFI 3rd gens in 1984 (except the 4 cylinders). So, originally your car had a carb. If it's the original carb, that's a good thing, because it is the type that is most likely to succeed. The 350 doesn't matter, as long as the cam in it is reasonable. The easiest and cheapest way to pass emissions with a factory computer command carb is to get the system working the way it is supposed to work. New spark plugs, wires, cap, rotor, O2 sensor, fresh oil change, timing set where it is supposed to be, carb adjusted to specs, and use E10 gasoline (10% ethanol).

Carb: Edelbrock 600 CFM Carb (this is brand new)

The 350 is out of a '79 camaro z/28, its brand new as well..

Thay dident make an IROC-Z in 84 it came out in 85

+1

anyway, they do make this stuff that you put in your gas to help you burn cleaner.. i have heard of it before and have heard that it works. not sure how well, or what it is tho

get the car running HOT before the test. before i put the cat back on i failed at 180*, so i drove into the lot, turned off my fan and ran her up to about 245* and then tested... passed.

245* for any amount of time would most cause serious damage. if not immediate, definately in the long run. At that temp the motor would begin to self destruct, the water would be boiling, and the oil breaking down.

As stated earlier, retard the timing, and it wouldn't hurt to put a couple bottles of rubbing alchohol in about a half tank of gas. My IROC would fail every time till I started doing this a few years ago. I also had a 83 firebird that had a 350 TPI with all the emission stuff removed and it passed easily too.

Oh yeah, they may reject you if the leaks are really bad.....happened to me once before.

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I see you folks are talking about testing in 83's and what not. You would think cars as old as this they would give some sort of leeway. Isnt there a cut off year where if your car is older than this year you are not subject to emissions?

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my car had a waiver on the emissions last year. could only drive it 5,000 miles of less until i had it took it back again or something to that effect. i think in pennsylvannia your car has to be 25 years to be an antique, and then your waived from emissions.

What distributor? The stock one, or one with mechanical/vacuum advance?

You still haven't said what the emissions testing and/or inspection requirements are. Do you live in California or New Jersey? In California (and other places), you aren't going to get past 1st base with an Edelbrock carb - that being visual inspection.

Is the A.I.R. system still in place?

Most of the advice you've been given here is worth exactly what you paid for it.

Move to good ole TEXAS!

Inspection here is your blinkers, headlights, horn, drive and reverse. and Voila! You passed!

Move to Illinois-In Feb. of '07 if your car is older than '96 you don't have to take the test in most of the counties. the emmissions people are changing the type of test they do.

I just passed last week with my '86 and am taking my '92 today. One thing I found was to have a good CAT, a good tune and a recent oil change. Never failed if I had thise three in working order but after the test today I never have to go again.

...Unless you live in an emissions-controlled area, *cough* Dallas *cough*, in which case you have to do like me and try to pass emissions...

What I did is get this additive called RXP (I'd heard it worked before, and it seems to have), changed the oil (used an oil additive from Autozone, don't remember what it was called), changed the spark plugs, etc., and ran it using 93 Octane.

I barely slid under the wire (which is saying something with this car), but passed.

1/4 tank and a couple bottles of heet