AZ guys: emissions q's

[Bad Karma]

I have a '77 Suburban 1/2-ton 2wd with a 454/TH400. I found a crack in my driver-side exhaust manifold, a perfect excuse to put headers on... Anyway, anyone have any trouble getting through the Maricopa County emissions visual check with headers? Also, my truck has dual cats. Are they required on 1977 models?

Thanks!

 

[az-k5]

I believe cats were requires 78 and up on AZ GM 1/2 tons. I had a single cat on my '80.

 

[Bad Karma]

That's what I heard/read also... The first time I took it through emissions, the box for catalytic converter was marked "N/A", but the next year it said "passed" or yes or something. Since headers will probably require a new exhaust system, I was thinking of ditching the cats...

 

[dyeager535]

If visual, you SHOULD fail for dual cats as well, but that depends on locality as to whether they actually enforce that.

 

[az-k5]

The dweebs at the emisions place don't know what to look for anyway. A 1977 doesn't require cats, but they do help the numbers a lot.

Last year I almost got a kid fired during the inspection cause he asked if my cats were hollowed out (I passed but was real close to the numbers and he was being a smart azz). I asked if he knew how to tell. (he responded with a puzzled look) I then said you can tap it with your knuckles and if it goes "thud" it is real, but if it goes "ting" it is hollowed. He then got on his hands and knees to check. This is when I caught the supervisor coming over yelling (this kid was about to burn his hand off). Ediots I tell ya.

 

[supersize75k5]

I have taken a few though, all with headers, cats dont rob to much in all reality from what I am hearing anyways, although the extra cost sucks...

I say get a replacemnt maninfold for cheap "there everywhere" then after you have gone though emmisions do your exaust system, but that just prolongs the problem for the next time you have to do the test,

 

[pauly383]

What does the sticker in the glovebox say ?

There is a 78 Burb in my backyard that came with dual exhaust and no cats factory , and its on the glovebox rpo list . Its based on GVWR I believe , heavy emissions on some models . My K5 in the garage is a 77 tub , and that came without cats factory as well .

 

[pauly383]

Just do it right the first time , no worries , no problems . with everything in life , do it right first time

 

[4xcrazy]

Headers are not a problem, emission eguipment attached to the stock manifolds is where you run into problems with aftermarket headers, if it has air tubes, those need to be fabbed in, or bought that way.

if your truck came from the factory WITHOUT a Cat, then remove it, don't need it, as mentioned, all it does is makes the numbers look good anyways.

I personally am not a fan of true dual exhaust anymore, there are much easier, simpler ways to get a good flowing exhaust without the extra time, weight and money it takes to fit up a dual system.

 

[Bad Karma]

I'll have to look for the glovebox sticker, I've never noticed if it was there or not... As far as emission equipment goes, it only has a PCV valve and a thermo-switch (that doesn't work) for the distributor advance. No air injection, EGR, or anything else. I suspect the cats were installed by the previous owner, but I guess it wouldn't hurt to leave them.

 

[kgblazerfive]

Cats didn't come on chevy trucks until 78 then it was an option, California is probally different though. the easiest way to tell is what your fuel door looks like if you have one then it came with cats if you don't then it didn't come with cats. Non cat trucks will jist have the cap on the outside no door.