Smog Pump Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

72 Cheyenne K20 · 07-19-2006, 10:30 AM

I'm trying to put my 72 K20 as close to factory as I can and wanted to know if smog pumps came on this model. I think I remember reading that smog pumps only came on c/k 10 models. Any truth to this? Would it be listed on the glove box ID? Thanks in advance for the help guys.

Scott

SoCal71K20 · 07-19-2006, 02:29 PM

I've got a '71 K20 from California, it never had a smog pump, only PCV valve at valve cover. This is with 350 with Quadrajet. Was told long ago that K20's didn't have 'em cause Feds did not require at the time 3/4 ton trucks and heavier. Not sure that was the real reason or not. Sounded good. Good luck.

farside847 · 07-19-2006, 04:59 PM

The california smog pump and air injection headers started in 1973 (had one, what a PITA). I have a 71 now and it never had a pump. I think your safe.

toms68cst · 07-19-2006, 11:28 PM

Are your exhaust manifolds original? Are there plugs were the smog system went in? Being yours is a K/20 I'm guessing it lacked a smog pump.

From what I can tell, 1/2 ton manual trucks from 68 until 70 somthing up had smog pumps. I'm not sure about 4x4's though. They could have a different set of rules.

My 68 1/2 ton 4 speed has a smog pump. It was sold in ND originally.

72 Cheyenne K20 · 07-19-2006, 11:43 PM

Good point on the exhaust manifolds Tom, I have the original center dump manifolds and no plugs. I guess the ole girl came without. Thanks for all the input guys. Thats why I love this board.

Scott

07-19-2006, 10:30 AM	#1
72 Cheyenne K20 Registered User Join Date: Feb 2003 Location: Staunton, Virginia Posts: 554	Smog Pump Question I'm trying to put my 72 K20 as close to factory as I can and wanted to know if smog pumps came on this model. I think I remember reading that smog pumps only came on c/k 10 models. Any truth to this? Would it be listed on the glove box ID? Thanks in advance for the help guys. Scott

07-19-2006, 02:29 PM	#2
SoCal71K20 Registered User Join Date: Jan 2002 Location: Lemon Grove, California Posts: 152	Re: Smog Pump Question I've got a '71 K20 from California, it never had a smog pump, only PCV valve at valve cover. This is with 350 with Quadrajet. Was told long ago that K20's didn't have 'em cause Feds did not require at the time 3/4 ton trucks and heavier. Not sure that was the real reason or not. Sounded good. Good luck.

07-19-2006, 04:59 PM	#3
farside847 Registered User Join Date: Feb 2005 Location: Bay Area, California Posts: 995	Re: Smog Pump Question The california smog pump and air injection headers started in 1973 (had one, what a PITA). I have a 71 now and it never had a pump. I think your safe. __________________ 1971 Chevy C10 Shortbed Stepside, 307v8 3-on-the-tree

07-19-2006, 11:28 PM	#4
toms68cst Registered User Join Date: Jun 2000 Location: Bismarck, ND Posts: 4,297	Re: Smog Pump Question Are your exhaust manifolds original? Are there plugs were the smog system went in? Being yours is a K/20 I'm guessing it lacked a smog pump. From what I can tell, 1/2 ton manual trucks from 68 until 70 somthing up had smog pumps. I'm not sure about 4x4's though. They could have a different set of rules. My 68 1/2 ton 4 speed has a smog pump. It was sold in ND originally. __________________ Unrestored 68 C-10 CST. Original 327. 4-Speed CH465. 50k or so miles. TREASURER, Drum Brake Club.

07-19-2006, 11:43 PM	#5
72 Cheyenne K20 Registered User Join Date: Feb 2003 Location: Staunton, Virginia Posts: 554	Re: Smog Pump Question Good point on the exhaust manifolds Tom, I have the original center dump manifolds and no plugs. I guess the ole girl came without. Thanks for all the input guys. Thats why I love this board. Scott

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