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#1 |
Registered User
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Location: Dallas Texas
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Gas Cap Identify Help
http://67-72chevytrucks.com/vboard/s...d.php?t=178829
I found the above post by Joesjunk from 2005. He was asking the same question I am. Reading his thread I still can't figure out what this cap fits. I have a gas cap GM3927086 and I don't know what it fits. Says "pressure vacuum" on the inside of the cap. Any help would be appreciated. Thanks |
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#2 |
Senior Member
![]() Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,110
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Re: Gas Cap Identify Help
What year is your truck? Half ton, or bigger?
'72s had a narrower fill neck diameter, and in 1/2 ton, had EEC emissions connections, like a return line from the carb, and a charcoal evaporator in the engine bay. Earlier trucks and 3/4, and 1 tons didn't require emissions stuff. Some gas caps were vented, some non-vented. If you take the gas cap off, is there a whoosh?
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Every 25 years I like to rebuild that 292, whether it needs it or not. |
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#3 |
Registered User
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Location: Dallas Texas
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Re: Gas Cap Identify Help
My truck is a half ton. The cap in question is a nos cap I have on the shelf and need to know what trucks it fits. I am clearing out my shelves so before I put this cap up for sale I'd like to have some more information. This is not a for sale thread. Thanks for your help
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#4 |
Senior Member
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Location: Independence MO.
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Re: Gas Cap Identify Help
Not sure on the part number, but can you post a picture of the front and back of it?
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#5 |
Carpe manana
![]() ![]() Join Date: Dec 2010
Location: Eau Claire, WI
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Re: Gas Cap Identify Help
See this thread beginning w post #46: https://67-72chevytrucks.com/vboard/...d.php?t=810278
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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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#6 |
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Location: Dallas Texas
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Re: Gas Cap Identify Help
Pics of the cap
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#7 |
Registered User
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Location: Dallas Texas
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Re: Gas Cap Identify Help
one more photo. again this is not a for sale thread. thanks for your help.
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#8 |
Senior Member
![]() Join Date: Feb 2002
Location: Tucson, AZ USA
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Re: Gas Cap Identify Help
''Pressure Vacuum'' probably means Non-Vented.
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Every 25 years I like to rebuild that 292, whether it needs it or not. |
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#9 |
Senior Member
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Location: Falls City, Nebraska "100 Miles From Nowhere"
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Re: Gas Cap Identify Help
Found this... https://67-72chevytrucks.com/vboard/...d.php?t=818739
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Michael of the clan Hill, "Two Seventy Two's" 71 1-ton Dually 350 4-Speed 71 C/50 Grain Truck, 350 Split-Axle 4-Speed 02 3/4 ton Express 14 Indian Chief Vintage 1952 Ford 8N, "Only Ford Allowed On The Property" ![]() "Be American, Buy American" ![]() |
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#10 |
Registered User
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Location: Dallas Texas
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Re: Gas Cap Identify Help
Thanks all for the help.
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#11 |
Registered User
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Location: Maquoketa, Ia/ Orr, Mn
Posts: 2,976
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Re: Gas Cap Identify Help
I found this when I googled the part number;
http://www.gmpartswiki.com/getpage?pageid=218675
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#12 |
Post Whore
![]() Join Date: Feb 2016
Location: Portland Oregon
Posts: 10,911
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Re: Gas Cap Identify Help
That would appear to make it a vented cap. I believe the vented caps for those years would hold 2 or 3 psi of pressure before venting air out of the tank. Hence the "Pressure Vacuum" stamping.
It was to keep fuel from sloshing out of the fuel fill when going around right hand corners when the tank is more than 1/2 full. My Burban has that problem as the locking cap I have isn't vented correctly.
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Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. ![]() RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
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#13 |
Senior Member
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Location: Tucson, AZ USA
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Re: Gas Cap Identify Help
I quit using locking caps years ago. I found I lost more gas making hard rights than was ever likely to be siphoned out by theives. [The original use of the Canadian insult ''Hosers'' referred to gas siphon theives.]
Also when I lost the cap lock key, and had to musclef@%$ it off -- the neck was damaged and I wound up swapping in a '67 tank. After hot tanking it, painting the outside spraycan Aluminum and putting in a new float assembly. And of course, the sender reads all different now. The cap I have on the Stepside now goes ''Whoosh'' when I crack it open.
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Every 25 years I like to rebuild that 292, whether it needs it or not. |
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