Which of the '73-'80 Chevy's had catylitic converters and which didn't?

['65 Super Sport 327 700R4]

I am sort of lost here, I have 4 buddies that have '73-'80 Chevys and half of them have cats and half don't. The ones that don't have them are a '78 Camper Special with a 350 and a 4-speed, and the other one is a '74 C10 short bed with a 350 and TH350 trans. The ones that have cats are a '75 C10 "BIG TEN" short bed with a 350 and TH350 trans, and the other one is a '78 C10 short bed with a 350 and TH350 trans. Why do some of them have catylitic converters and others don't.
I have a neighbor who had an '85 C20 scottsdale that came with a 6.2 diesel, but it was replaced with a 350. He doesn't have to go through emisions because it was a diesel. I am thinking about picking it up and dropping in a stout big block, with a carb and no emisions controls.

Thanks,
Erik

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'29 Chrysler model 65 all original, 2nd owner ***FOR SALE***
'63 Impala SS 283, 3-on-the tree, flowmaster 2 1/4" dual exhaust, performer intake, edelbrock 600 carb, chrome 15x8 rally's
'64 Impala 4-door 126,000 miles, we just got from original owner, shes 93.
'65 Impala SS, built 332, 700R4, 3.73, 2 1/2" mandral bent duals w/H pipe, Flowmaster 40-series deltaflows, MSD Mallory, too many modifications to list
'72 Chevy Suburban 4x4, NP205, TH350, balanced 357 (.040 350), 268 high energy cam, 9.2:1 comp, 1.94/1.50 heads (ENGINE BUILT BY THE GREAT RAYZOR or if you know him RAY, WHO POSTS ON THIS BOARD AND CHEVYTALK), 3/4 ton leaf springs, 4" lift, 35/12.5/16.5 Grabber MT's, Rancho shocks, Rancho dual steering stabalizer, American Eagle 143's 16.5x9.75 6 lug, 4.10's, 12 bolt rear limited slip, Dana 44 front limited slip. Carter 600, performer intake, headers and flowmaster exhaust system very soon.
'95 Impala SS Flowmaster cat-back, K&N, 285/40/17 Firehawks, Dark cherry metallic, 27,000 miles, extreamly fun vehicle
'95 Chevy K2500, ex-cab, long bed, 350, AT, Flowmaster cat-back, 265/75/16 Mud Kings, 16x7.5 Centerline HT cast
wheels, Leer high rise canope, bed liner w/ mat, loaded.**FOR SALE**

[Big 10]

Hi,
I'm not quite sure, but I think that'73 was the only year that they didn't come with cats, maybe '74 too. Ithink after that they were required by the government to have them. Up here in ND, though, I would say that over 90% of these older trucks have had the cats removed by their owners. I know that mine started on fire and had to be removed 19 years ago... I'm not totally sure on this, but that's how I remember it being, there might be exceptions...

Eric

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'80 Chevy Cheyenne 1/2 350 4bbl.

['65 Super Sport 327 700R4]

Hey Eric,

I wonder why my friends '78 camper special doesn't have cats? He said it still has the original exhaust system and I looked under there and saw there are no cats. I wonder if since its a heavy duty truck it wasn't required to have converters.

Thanks,
Erik

------------------
'29 Chrysler model 65 all original, 2nd owner ***FOR SALE***
'63 Impala SS 283, 3-on-the tree, flowmaster 2 1/4" dual exhaust, performer intake, edelbrock 600 carb, chrome 15x8 rally's
'64 Impala 4-door 126,000 miles, we just got from original owner, shes 93.
'65 Impala SS, built 332, 700R4, 3.73, 2 1/2" mandral bent duals w/H pipe, Flowmaster 40-series deltaflows, MSD Mallory, too many modifications to list
'72 Chevy Suburban 4x4, NP205, TH350, balanced 357 (.040 350), 268 high energy cam, 9.2:1 comp, 1.94/1.50 heads (ENGINE BUILT BY THE GREAT RAYZOR or if you know him RAY, WHO POSTS ON THIS BOARD AND CHEVYTALK), 3/4 ton leaf springs, 4" lift, 35/12.5/16.5 Grabber MT's, Rancho shocks, Rancho dual steering stabalizer, American Eagle 143's 16.5x9.75 6 lug, 4.10's, 12 bolt rear limited slip, Dana 44 front limited slip. Carter 600, performer intake, headers and flowmaster exhaust system very soon.
'95 Impala SS Flowmaster cat-back, K&N, 285/40/17 Firehawks, Dark cherry metallic, 27,000 miles, extreamly fun vehicle
'95 Chevy K2500, ex-cab, long bed, 350, AT, Flowmaster cat-back, 265/75/16 Mud Kings, 16x7.5 Centerline HT cast
wheels, Leer high rise canope, bed liner w/ mat, loaded.**FOR SALE**

[Big 10]

Hey Erik,

It's a posiblity that they didn't require the heavy duty pickups to have cats on them. I don't really know anyone that has a heavy duty pickup. I do know that my '80 Big Ten C10 had one from the factory though. Around here no one is really concerned where or not their pickup is supposed to have a cat, they just take them off anyway....

Eric

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'80 Chevy Cheyenne 1/2 350 4bbl.

[Fast68Chevy]

ALL '75-up trucks have them. How does he know the '78 is all orignal on the exhaust, those pipes cant be 23 years old and still be on the truck.
Has he owned the truck since new ?

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Its all going.... selling/scrapping everything ! Anything I have, its for sale, even the new oxy/acetylene torch set-up
Randy

5470 posts 4-30-01
http://communities.msn.com/RandyR72K5
1968 LWB C-10
1972 CST 4x4 K-5
Lincoln, IL
"life's gonna leave me in the dust, if I don't try and catch up to it soon"
r72k5@hotmail.com
[EMAIL]

['65 Super Sport 327 700R4]

It only has 70,000 miles on it. He is the second owner, but he got it back in '80. It was all original then and still now, except he put 33/12.5/16.5 Bridgestone Desert Dueller out back. Other than the tires its all original and in outstanding condition.

Thanks,
Erik

------------------
'29 Chrysler model 65 all original, 2nd owner ***FOR SALE***
'63 Impala SS 283, 3-on-the tree, flowmaster 2 1/4" dual exhaust, performer intake, edelbrock 600 carb, chrome 15x8 rally's
'64 Impala 4-door 126,000 miles, we just got from original owner, shes 93.
'65 Impala SS, built 332, 700R4, 3.73, 2 1/2" mandral bent duals w/H pipe, Flowmaster 40-series deltaflows, MSD Mallory, too many modifications to list
'72 Chevy Suburban 4x4, NP205, TH350, balanced 357 (.040 350), 268 high energy cam, 9.2:1 comp, 1.94/1.50 heads (ENGINE BUILT BY THE GREAT RAYZOR or if you know him RAY, WHO POSTS ON THIS BOARD AND CHEVYTALK), 3/4 ton leaf springs, 4" lift, 35/12.5/16.5 Grabber MT's, Rancho shocks, Rancho dual steering stabalizer, American Eagle 143's 16.5x9.75 6 lug, 4.10's, 12 bolt rear limited slip, Dana 44 front limited slip. Carter 600, performer intake, headers and flowmaster exhaust system very soon.
'95 Impala SS Flowmaster cat-back, K&N, 285/40/17 Firehawks, Dark cherry metallic, 27,000 miles, extreamly fun vehicle
'95 Chevy K2500, ex-cab, long bed, 350, AT, Flowmaster cat-back, 265/75/16 Mud Kings, 16x7.5 Centerline HT cast
wheels, Leer high rise canope, bed liner w/ mat, loaded.**FOR SALE**

[Fast68Chevy]

Someone has removed the catlytic converter.

[Captkaos]

Most trucks over a certain Weight (Towing) is exempt from Cats. 3/4 tons I have seen didn't come with them. '75 was the first year for catalytic converters and you can be sure it had them if it has "unleaded fuel only" on the fuel guage and it has the small throat fuel filler. Some 75 had them, some didn't. Everything 1/2 ton after it had cats. As for the Camper specials, due to the load capacity, they were possibly exempt.

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Chris Lucas
1973 Chevy C-10
1975 Chevy Silverado
Captkaos' Page

[rick@its]

I have a 77 1/2 ton with a 350 auto and no cat, It did not come with one as the underhood sticker says nothing about catalyst or AIR. The only emission equipment it has is an evaporative canister. This truck is considered Heavy Duty because of the GVW (6700 I think)

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Rick
Broken Arrow, OK
72 cheyenne (in pieces)

[u2slow]

My father's 79 20-series crewcab camper special 454 had cats, A.I.R, smog pump, EGR, unleaded fuel, charcoal canisters, 2-into-1-into-2 exhaust. You name it, it had it.

My buddy's '80 K20 Custom had a PCV valve and that's it. All factory.

I've heard 1-tons went right till 85 or so without any cats.

The bottom line is, it depends on how your truck was originally outfitted. There are at least three levels of emissions equipment I know of: Federal, California, and High-altitude. It seem the equipment for each level depends on the particular model year.

[KIILew]

Even though this is an old topic, I am new to this board, and since I know the LONG answer to this question, I can't resist posting a response...Please bear with me!

Basic Federal (i.e. non California) emission laws are as follows for gasoline fueled vehicles:

For 1973 to 1978 all passenger cars and light trucks under 6,000 lbs GVWR must meet stringent light duty emission standards. All trucks heavier than 6,000 lbs GVWR must comply with heavy duty emission standards, which are much more lenient. For 1979 through the current day, the dividing line between light and heavy duty emissions was raised from 6,000 lbs GVWR to 8,500 lbs GVWR, forcing more trucks to comply with the stricter emissions standards than previously.

California emission history is identical with one exception: that state raised the heavy duty emission threshold for California-sold vehicles from 6,000 lbs GVWR to 8,500 lbs GVWR a year earlier, for 1978. (I.E. the Federal Government followed California's lead a year later, for 1979.)

A few other general facts:

Catalytic converters were introduced into the auto industry for the 1975 model year. From 1975 on, catalytic converters were used on ALMOST all light duty emission standard vehicles (all states) but were not used on any heavy duty emission standard vehicles. When auto manufacturers adopted fuel injection in their light and heavy duty emission class vehicles, they adopted the use of catalytic converters across the line. (GM adopted fuel injection and cats essentially across the line for 1987.)

...What all of the above means for 1973 to 1987 Chevy C/K series trucks follows:

For 1973 thru 1974, no converters on any models, anywhere.

For 1975 thru 1977, catalytic converters were used on all C/K 10/15 trucks nationwide with GVW's under and up to 6,000 lbs, except 1976 and 1977 C10/15's with the 454 V8. Models with GVW's over 6,000 lbs (i.e. all 1975-77 C10/15's with the F44/Big 10/Heavy Half, all 1976 and 1977 K10/15's and all 1975, 1976, and 1977 C/K 20/25/30/35's) did not use catalytic converters.

For 1978, all C10/15's with GVW's under 6,000 lbs have converters regardless of engine. All other '78 models (i.e. Big 10's/Heavy Halfs, K10's, C/K 20/25/30/35's)had GVW's over 6,000 lbs, and therefore did not use converters. EXCEPTION: For 1978, all California models with GVW's under 8,500 lbs had cats. Therefore, this California exception included ALL and ONLY 10/15/20/25 series vehicles, including Big 10's/Heavy Halfs.

For 1979, Federal laws, like California statutes in '78, raised the GVW threshold. So, all 1979 models, except for C/K 30/35 vehicles, had cats, nationwide.

For 1980 through 1986, the same models as those for '79 used cats. However, a new C6P heavy duty option was offered for C/K 20/25 models which provided an 8,600 lb suspension package. These new, heavier 3/4 tons cleared the 8,500 lb limit, and so did not use converters during this time period, nor did C/K 30/35's.

For 1987 and beyond, all Chevy/GMC fuel injected engines used cats regardless of location or weight class. Only a few 30/35 series chassis cab models offered carburated 292, 350 and 454 engines, and those were the only models that did not use catalytic converters for 1987 on.

Note: the above discussion applies only to U.S. vehicles. Canadian Chevy/ GMC trucks followed a much simpler story, I think. From what I have seen, no Canadian carburated Chevy/ GMC C/K/R/V used cats, while all '87 and later fuel injected models did.

End of story!

[Longhorn Man]

Interesting fact, I think in 2000, maybe 2001, the government passed that all light duty trucks have to meet passenger car standards.

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'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
Need to pick up the one ton Longhorn with a PONTIAC 350/350soon.
Thanks every one!
Check out The Longhorn Webite.
If you need a pic posted, E-mail me at longhornmail@yahoo.com
Andy, in Columbus Ohio

[gmtruck71]

KIILEW, You are exactly on the money about the cat thing. Having the opportunity to have owned C series and K series 10-20 series trucks in 77,78,and 79. Your info reflected what was on my trucks. Another piece of info is that trucks with cats had the words UNLEADED FUEL ONLY on the fuel gage. Trucks without cats did not say this. All my trucks were not california.

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Marty Hall
Taylorsville, Ky
1971 C-10 SWB fleetside (355,700-R4)
1971 K-10 LWB Cheyenne (454\turbo-400)
1972 C-10 SWB stepside (6-cyl)
1949 3100 chevy panel delivery
(original)
93 S-10 Blazer
93 S-10 Pickup

[jeff69cst/10]

My 79 k/20 gvw 8600# had a cat.
My dads 79 F-150 that he ordered brand new and still owns had no cat,it's a 6 cyl.

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69 CST/10 350/400TH lwb fleet all original,1 owner
79 K/20 4x4 built & lifted
Sheridan,IN

[DRASTiK]

sorry to bring back this old post guys, but I need to find out whether or not this truck came with cats. According to the above info, unless this is a heavy duty truck, then it required cats. I'm not sure if it is classified as heavy duty or not. It came with a tow package and a 454.

it's a 78 1/2 ton short bed. the vin is:

TCS448Z526228

Thanks in advance,
Dave

[apstguy]

:p Here in Califronia, we DO have to worry about emissions crap. It sucks a big one.

Originally posted by Big 10
Hey Erik,

It's a posiblity that they didn't require the heavy duty pickups to have cats on them. I don't really know anyone that has a heavy duty pickup. I do know that my '80 Big Ten C10 had one from the factory though. Around here no one is really concerned where or not their pickup is supposed to have a cat, they just take them off anyway....

Eric

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'80 Chevy Cheyenne 1/2 350 4bbl.

[78SilveradoSWB]

I have a 1978 C-10 equipped with a 454 engine. It was built in the first part of 1978 and did not have a cat converter. It is not a California truck either. I believe in the latter part of the 78 model year, they added the gas doors and the cats, and other emission stuff. A good clue is the unleaded fuel only stickers on the dash and gas fill. Leaded gas is a no-no for cats (and felines too )

[78burban]

this link explains it all thanks swerve for the info

http://www.73-87.com/7387stuff/7387emislevel.htm

[swervin ervin]

Thanks should go to KIILew. This is his info. I just put it on my site. The same info is also posted by him above.

[78burban]

you know i got a 1978 suburban its 6800 gvwr. it had no cat on it but im in the process of restoring it and going to go with a 383 stroker with a 700 cfm holley or maybe a stock quadrajet. i wonder how much emmission that motor will put out any tips on keeping the emmission down. Also i was wondering if any1 here is from tn or nashville for that matter i would like to meet up with some people and mayube share some ideas.

[DRASTiK]

There is no "unleaded fuel only" on it anywhere, but I don't see how it would be a 6000lb truck either. It's kinda confusing.

[78burban]

nope no unleaded fuel anywhere i just checked when i saw this post and the door sticker says 6800 gvwr you got to remeber this a suburban not a truck its a bit more heavier.

[DRASTiK]

I wasn't directing that directly towards you. I was referring to the information above that states what years had cats with exceptions for the heavy duty trucks. Sorry for the confusion.

Dave

[J-Spec C10]

In canada it went like this, all 73-75, no cats. 76 on, all had cats. This applies to all cars/trucks.

[Marks 85]

The cat question has undoutably been answered, but what about smog pumps?