Quadrajet info needed. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Slofarmtruck · 06-18-2010, 08:56 PM

When I bought my truck I just threw a new edelbrock carb on to ease the resurrection of a sitting for 10 years vehicle. I also removed all the emissions components that I could. I later figured out that due to the faulty gas gauge the truck was out of fuel. The truck runs good now. With that said I am going to try the quadrajet back on the truck again. My question for all you experts is, what vacuum ports can I block off on the stock quadrajet and which one is my vacuum advance for the distributor? Pictures are greatly helpful and appreciated.

79gmcc15 · 06-18-2010, 10:37 PM

Well you really just need 3 ports open. One full time for your pcv filter, one ported for vac advanced *or full if you go that way* and the vacuum line for your brake booster should be screwed into the back of the Carb on the base plate. So that's it. Your trans line should be screwed in to the manifold.

ray_mcavoy · 06-18-2010, 10:40 PM

This shows the (now discontinued) Edelbrock versions:

The top pic (1901/1902) carbs were modeled after the early 4MV style Q-Jets that were used on cars until 74 and later on some pick-up truck applications.

The middle pic (1903/1904) carbs were modeled after the M4MC style Q-Jets that were used on many 75-up applications.

Slofarmtruck · 06-18-2010, 11:09 PM

Thanks a lot!! The pictures help perfectly. We'll see how she runs tomorrow.

Slofarmtruck · 06-19-2010, 07:46 PM

Quadrajet is on and she runs great!! My only question now is. Attached to the thermostat housing is a switch that has a single black with green stripe wire attached to it which than goes to the carb into another harness. What is that switch called? Mine is broken physically and I would like to replace it. I tried coolant switch at the auto parts store but came up empty. Again any help is appreciated.

Slofarmtruck · 06-19-2010, 10:13 PM

Looks like I'm looking for the choke Temperature switch. If anyone knows where I can find one please let me know as I can't locate it online or at the local auto parts store. I have not tried Napa yet but will on Monday.

06-18-2010, 08:56 PM	#1
Slofarmtruck Registered User Join Date: Feb 2010 Location: Waukesha, WI Posts: 162	Choke Temp switch help! When I bought my truck I just threw a new edelbrock carb on to ease the resurrection of a sitting for 10 years vehicle. I also removed all the emissions components that I could. I later figured out that due to the faulty gas gauge the truck was out of fuel. The truck runs good now. With that said I am going to try the quadrajet back on the truck again. My question for all you experts is, what vacuum ports can I block off on the stock quadrajet and which one is my vacuum advance for the distributor? Pictures are greatly helpful and appreciated. Last edited by Slofarmtruck; 06-19-2010 at 10:11 PM. Reason: change title

06-18-2010, 10:37 PM	#2
79gmcc15 Gettin It One Pice At A Time Join Date: Oct 2004 Location: everett, washington Posts: 2,688	Re: Quadrajet info needed. Well you really just need 3 ports open. One full time for your pcv filter, one ported for vac advanced or full if you go that way and the vacuum line for your brake booster should be screwed into the back of the Carb on the base plate. So that's it. Your trans line should be screwed in to the manifold. __________________ RIP ELJAY Work In Progress 1979 GMC C1500 Trailering Special. Getting the truck done, one piece at a time. “You can tell a lot about a fellow’s character by his way of eating jellybeans.”Ronald Reagan “I don’t know the key to success but I know the key to failure is trying to please everybody.” Bill Cosby Last edited by 79gmcc15; 06-18-2010 at 10:45 PM.

06-18-2010, 10:40 PM	#3
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,359	Re: Quadrajet info needed. This shows the (now discontinued) Edelbrock versions: The top pic (1901/1902) carbs were modeled after the early 4MV style Q-Jets that were used on cars until 74 and later on some pick-up truck applications. The middle pic (1903/1904) carbs were modeled after the M4MC style Q-Jets that were used on many 75-up applications.

06-18-2010, 11:09 PM	#4
Slofarmtruck Registered User Join Date: Feb 2010 Location: Waukesha, WI Posts: 162	Re: Quadrajet info needed. Thanks a lot!! The pictures help perfectly. We'll see how she runs tomorrow.

06-19-2010, 07:46 PM	#5
Slofarmtruck Registered User Join Date: Feb 2010 Location: Waukesha, WI Posts: 162	Re: Quadrajet info needed. Quadrajet is on and she runs great!! My only question now is. Attached to the thermostat housing is a switch that has a single black with green stripe wire attached to it which than goes to the carb into another harness. What is that switch called? Mine is broken physically and I would like to replace it. I tried coolant switch at the auto parts store but came up empty. Again any help is appreciated.

06-19-2010, 10:13 PM	#6
Slofarmtruck Registered User Join Date: Feb 2010 Location: Waukesha, WI Posts: 162	Re: Quadrajet info needed. Looks like I'm looking for the choke Temperature switch. If anyone knows where I can find one please let me know as I can't locate it online or at the local auto parts store. I have not tried Napa yet but will on Monday.



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