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#1 |
Senior Member
![]() Join Date: Feb 2001
Location: Killen, Alabama USA
Posts: 3,574
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3/4 ton big block with SMOG?
Just pulled in a 3/4 ton Suburban with 402 and TH400. It is a TLM suffix code engine with SMOG on it. All 3/4 BB trucks I’ve seen have been non-SMOG. Was this a Burb thing or assembly plant thing? It is a Flint built truck. All dates appear to match up with blue sticker on door so I don’t think the engine has been changed out. Any ideas?
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72 Cheyenne Super swb. Factory 402/400,tach,posi,AM/FM, A/C. Adding cruise, 8-track 72 Cheyenne Super swb. 350/350 A/C, bucket seats 72 Cheyenne swb. Factory 402/400, tilt, posi, A/C 72 Cheyenne Super K-10. 350/4 spd., posi. 72 Suburban 350/350 tilt, tach, AM/FM, A/C, luggage rack 72 GMC Sierra lwb. 350/350, A/C. medium green/olive interior Last edited by JQ-72; 04-02-2024 at 11:29 AM. |
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#2 |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,440
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Re: 3/4 ton big block with SMOG?
What year vehicle/engine? And what SMOG equipment?
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~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
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#3 |
Senior Member
![]() Join Date: Feb 2001
Location: Killen, Alabama USA
Posts: 3,574
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Re: 3/4 ton big block with SMOG?
Oh yeah. 1972 with the air injector pump
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72 Cheyenne Super swb. Factory 402/400,tach,posi,AM/FM, A/C. Adding cruise, 8-track 72 Cheyenne Super swb. 350/350 A/C, bucket seats 72 Cheyenne swb. Factory 402/400, tilt, posi, A/C 72 Cheyenne Super K-10. 350/4 spd., posi. 72 Suburban 350/350 tilt, tach, AM/FM, A/C, luggage rack 72 GMC Sierra lwb. 350/350, A/C. medium green/olive interior |
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#4 |
Senior Member
![]() Join Date: Oct 2009
Location: Godley, TX
Posts: 17,962
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Re: 3/4 ton big block with SMOG?
TLM = 72 RPO L47 402 with Air Injection Reactor - applications show C10 and C20.
Yes, I find that surprising, I haven't seen smog on a C20 before either. TKM is also an L47 with AIR for C10 and C20. There are non-AIR codes for 72 big block C20/30 (only, i.e. not available on a C10) (TKW, TKX). |
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#5 |
Born Psycho
![]() Join Date: Feb 2001
Location: brentwood,cal,usa
Posts: 4,884
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years ago i had a 69 3/4 ton suburban 396 with air injection , it was a clean original truck and my dumb a$$ parted it out. sold the motor with all the brackets including a-c for more than i paid for the whole truck.
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jerry moss 72 cheyenne super K20- tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,tow hooks,bumper guards,toolbox,aux. fuel tank,posi front and rear,plus other goodies!!! SOLD 69 suburban K20-tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,4 inch all spring lift,4 speed, 14 bolt full floater, dana 44 HD,warn winch,posi front and rear,tow hooks,plus other goodies. 73/80 chevy/gmc K20 SB400,turbo 400,205,tilt,a-c,gas hog. 77 K/5 cheyenne blazer-daily driver/beater. SON HAS IT NOW BRENTWOOD,CALIFORNIA |
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#6 |
Senior Member
![]() Join Date: Feb 2022
Location: Ca
Posts: 517
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Re: 3/4 ton big block with SMOG?
A 1972 c20 has a commercial classification, so no calif smog equipment is/was required. C10 required smog as it was not classified commercial. It is why a c20 is more expensive to register in California because of commercial class. The c20 has commercial plate allowing you to park in yellow curb commercial zones. Useful in urban areas of LA, SF and SD. The Chevy Suburban, even the c20 Suburban was classified as a passenger vehicle so smog was required. You can get a C20 registered as passenger if you have a permanent camper on it to save a few bucks but a sharp eyed smog tech could have caused problems. Not a issue now. We are past inspection dates. If you need info on BB smog parts, I would look to the C3 Corvette owners. They likely have the info given there were a lot of BB Corvettes from that time. They were putting pumps on 250 sixers as far back as 1967 in calif. The air injector port was actually in the head, not the manifold. I owned every car/truckmentioned in this post except the suburban at one time or another.
Last edited by PbFut; 03-30-2024 at 10:39 PM. |
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#7 | |
Born Psycho
![]() Join Date: Feb 2001
Location: brentwood,cal,usa
Posts: 4,884
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jerry moss 72 cheyenne super K20- tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,tow hooks,bumper guards,toolbox,aux. fuel tank,posi front and rear,plus other goodies!!! SOLD 69 suburban K20-tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,4 inch all spring lift,4 speed, 14 bolt full floater, dana 44 HD,warn winch,posi front and rear,tow hooks,plus other goodies. 73/80 chevy/gmc K20 SB400,turbo 400,205,tilt,a-c,gas hog. 77 K/5 cheyenne blazer-daily driver/beater. SON HAS IT NOW BRENTWOOD,CALIFORNIA |
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#8 |
Senior Member
![]() Join Date: Oct 2009
Location: Godley, TX
Posts: 17,962
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Re: 3/4 ton big block with SMOG?
When I lived in CA, C10s required commercial tags if the bed was open. If bed had a cap or tonneau, it was not required. It drove me absolutely nuts that had I had to go weigh and register my 66 C10 swb as a commercial vehicle. Maybe things have changed and CA has seen the light.
Regardless, 2 of the 4 72 402 suffix codes indicate that there was indeed an AIR-equipped 402 built for C10s and C20s (trucks) in 72. And the other 2 suffix codes indicate that a C20 or C30 could have a 402 without AIR. Maybe the smog 402s in C20s were just uncommon, or driven by an individual state requirement. I'm still not quite clear on what drove whether or not AIR was required on a C20, truck or burb. |
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#9 |
Roadtrip!
![]() Join Date: Feb 2003
Location: Grand Rapids MN
Posts: 13,737
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Re: 3/4 ton big block with SMOG?
I pulled this from a 72 1/2 ton burb a few years back.
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67 gmc custom lwb dakota truck. Sold...And bought back 69 swb 4x4 project (in progress) 70 c-10 lwb texas truck 70 4x4/BB/bkts/posi/tach(retired) 70 swb (wifes) 70 jimmy camper 71 K-5 factory 2wd 71 cheyenne 4x4/tach/posi/ plow rig 71 Cheyenne20 BB, buckets, tach, tilt, 4 speed 72 jimmy CST wyoming rig 72 jimmy Colorado rig 72 lifted texas 4x4 3/4 ton burb 65 fury conv. 383/auto 65 chrysler 300 "L" 413 auto |
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#10 |
Born Psycho
![]() Join Date: Feb 2001
Location: brentwood,cal,usa
Posts: 4,884
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commifornia hasn't changed for the better, if anything is got worse. pickups still have to be registered commercial, my 80 K20 just cost me $304.00 for a year because of the GVWR, didn't have to smog it this year but will next year. I work in a shop that does smog's and they are tightening up on the passing numbers trying to get the older vehicles off the road. if you own an older jeep with a 6 cylinder that doesn't have an EGR you can forget about it passing even with a brand new catalytic converter.
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jerry moss 72 cheyenne super K20- tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,tow hooks,bumper guards,toolbox,aux. fuel tank,posi front and rear,plus other goodies!!! SOLD 69 suburban K20-tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,4 inch all spring lift,4 speed, 14 bolt full floater, dana 44 HD,warn winch,posi front and rear,tow hooks,plus other goodies. 73/80 chevy/gmc K20 SB400,turbo 400,205,tilt,a-c,gas hog. 77 K/5 cheyenne blazer-daily driver/beater. SON HAS IT NOW BRENTWOOD,CALIFORNIA |
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#11 |
Senior Member
![]() Join Date: Feb 2022
Location: Ca
Posts: 517
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Re: 3/4 ton big block with SMOG?
I was young, and as most, did not understand the a.i.r. pumps of the day. They were quite effective at afterburning hydrocarbons on engines used at that time. The extra belt and pullies were easy to remove and so off they came. In reality, very little power was needed to spin a smog pump. Give how bad the air was in LA county, compared to today, I must say that as invasive as the Calif pollution laws are, they are effective. Today's air quality, though still not great is way, way better.
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#12 |
Registered User
Join Date: Aug 2022
Location: Warren IN
Posts: 13
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Re: 3/4 ton big block with SMOG?
My 1970 GMC C/2500 with a 307 had smog on it. It was built in Canada and was mandatory there, even though it was imported to the U.S.
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1970 GMC C/2500 Ol' Green 2005 GMC Canyon Daily |
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#13 |
Senior Member
![]() Join Date: Mar 2003
Location: Colfax-California
Posts: 8,553
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Re: 3/4 ton big block with SMOG?
Having a pick up with commercial plates does allow you to park in loading zones though.
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#14 |
Registered User
Join Date: Feb 2007
Location: west coast
Posts: 3,374
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Re: 3/4 ton big block with SMOG?
Another '70 307 3/4t 4x4, was surprised to see the smog equipment, was a U.S. Tarrytown build.
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#15 |
Senior Member
![]() Join Date: Feb 2001
Location: Killen, Alabama USA
Posts: 3,574
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Re: 3/4 ton big block with SMOG?
PbFut - thanks for the input. I didn’t know that the C20 Burb was considered a passenger car for smog purposes. Good info!
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72 Cheyenne Super swb. Factory 402/400,tach,posi,AM/FM, A/C. Adding cruise, 8-track 72 Cheyenne Super swb. 350/350 A/C, bucket seats 72 Cheyenne swb. Factory 402/400, tilt, posi, A/C 72 Cheyenne Super K-10. 350/4 spd., posi. 72 Suburban 350/350 tilt, tach, AM/FM, A/C, luggage rack 72 GMC Sierra lwb. 350/350, A/C. medium green/olive interior |
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#16 |
Registered User
Join Date: Dec 2020
Location: Joggins Nova Scotia
Posts: 1,598
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Re: 3/4 ton big block with SMOG?
i don't remember if that was required here or not back then,but whether it was or wasn't,if your truck was built in Canada and shipped to the U.S new,it would've built to the U.S spec.the other side of that coin is,i have hauled cars,trucks and Harley's home from the States for 40 years and we used to carry a booklet from Transport Canada,telling us what we could bring and home and what we couldn't,as some models were built to U.S specs that differed from Canadian specs.
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#17 |
Registered User
Join Date: Dec 2020
Location: Joggins Nova Scotia
Posts: 1,598
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Re: 3/4 ton big block with SMOG?
my 72 402 Cheyenne Super,built at the Fremont plant in Sept 71,has a TKX engine with no air pump or any other emissions equipment that i've found.it does say on the build sheet VJ9 Emission label,TF5 Cal Assy Emission and a YF6 Cal Proc Option? but there isn't or wasn't any emission equipment on it.
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#18 |
Carpe manana
![]() ![]() Join Date: Dec 2010
Location: Eau Claire, WI
Posts: 12,398
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Re: 3/4 ton big block with SMOG?
Here's a related thread for additional reference: THREAD
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1972 K5 CST Highlander Blazer: http://67-72chevytrucks.com/vboard/s...d.php?t=708547 1972 K20 Cheyenne Super: http://67-72chevytrucks.com/vboard/s...d.php?t=528308 ![]() |
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#19 |
425hp409
![]() Join Date: Oct 2008
Location: Prosper Texas
Posts: 841
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Re: 3/4 ton big block with SMOG?
SMOG - where built and where sold
I have a 67 Olds 442 with AIR. It was built in Fremont CA and sold at a California dealer so it had to have smog equipment. It is pretty unique at car shows here in Texas. If it was going to be shipped to a dealer out of California, the exhaust manifolds would have been plugged and no AIR even though it would have been built in California. I once saw a 66 Caprice with a 396 equipped with AIR. Good ole California smog rules. I have been in the mechanic field all of my life. I remember looking up emission specs for cars in the 60s and seventies and there were 2 categories; California and 49 states.
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Charles 68 SWB, Dad bought new, now 396 & factory ac 64 Impala SS, 409 425HP, 4 speed AC 64 Bel Air Wagon, 400 Small Block 57 Bel Air all original 283 w/Factory Air 77 GMC Sprint, 454/425HP 67 Olds 442, all original 90 ZR1 Corvette |
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#20 |
Registered User
Join Date: Jan 2011
Location: Chattanooga, TN
Posts: 2,151
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Re: 3/4 ton big block with SMOG?
I've never seen a BB Chevy head with AIR in the head?
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'83 K20-TPI '73 C10 '79 C10-ex-diesel(SOLD) '07 Tahoe(Son driving) '14 Suburban-DD '71 C10-current project |
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#21 |
Senior Member
![]() Join Date: Mar 2019
Location: Herculaneum MO (20 minutes south of St. Louis
Posts: 619
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Re: 3/4 ton big block with SMOG?
He didn't say they were. He mentioned a 250 in the preceding sentence. He's saying on the inline 6s they are in the head.
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67 C10 283 T5 swapped longbed fleetside = wife's daily driver 67 C20 292 (originally a 250)4speed longbed fleetside w/original wooden bed=my project truck 67 C10 283+.060 (so a 292 as well)T5 swapped longbed fleetside=my DD 72 C1500 Sierra Grande 350 TH350 longbed fleetside=wife's fair weather truck Can you tell we are fans of longbed fleetsides & 67s Chris |
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#22 | |
Registered User
Join Date: Apr 2014
Location: California
Posts: 950
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Re: 3/4 ton big block with SMOG?
Quote:
lol |
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#23 | |
Senior Member
![]() Join Date: Dec 1999
Location: Southern California
Posts: 2,810
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Re: 3/4 ton big block with SMOG?
Quote:
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Richard 1972 K10 Custom Deluxe SWB Fleetside My build https://67-72chevytrucks.com/vboard/...d.php?t=800746 |
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#24 |
Registered User
Join Date: Jan 2011
Location: Chattanooga, TN
Posts: 2,151
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Re: 3/4 ton big block with SMOG?
OK. I read it again. Gotcha!
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'83 K20-TPI '73 C10 '79 C10-ex-diesel(SOLD) '07 Tahoe(Son driving) '14 Suburban-DD '71 C10-current project |
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#25 |
Senior Member
![]() Join Date: Feb 2022
Location: Ca
Posts: 517
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Re: 3/4 ton big block with SMOG?
MarkTn: Sorry if I was not clear on the sixer I failed english more than once in my school days. I have never found the skill so my writing is clear to me, but most find it difficult to follow.
Mr Mudd: If your truck is a 3/4 ton then you are likely rocking commercial plates and are smog exempt in Calif. Another point was that if you purchased a used "Federal smog car", you could register in Calif. but you had to have the correct stickers on the car/truck and the smog inspection tech had to understand it was a Fed smog car. You still had to pass the minimum sniffer test to register. Later on things got tougher when the bi-annual inspections started but a used Federal car was allowed, again as long as the car could pass the sniffer. Someone mentioned that more of the manual trans cars got pumps, that is because the lifting of the accelerator to shift would lean the A/R ratio and cough out of plug of hydorcarbons. So I think it is possible that some motor tranny combos might have needed a pump even on a federal car. That is a guess on my part. Or maybe it was simply a Cal car moving to another state. There was a time around 1980-1982 when you could not get a manual trans and the 350 motor in Calif. If you wanted a manual, it was a 305 motor in the Corvette, Camaro and Trans Am. Not sure about trucks. |
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