4 barrel carb to a 2bbl carb - The 1947 - Present Chevrolet & GMC Truck Message Board Network

american revolution · 02-13-2011, 08:45 PM

have an 80 blazer that i use for a daily driver...4bbl carb on it that needs to get rebuilt soon...with the gas prices here in california (saying it might go as high as $4.50-5.00 per gallon by summer) thinking about changing to a 2bbl carb set up.

any negative issues with this?

BigBlocksRule · 02-15-2011, 09:12 AM

Yeah, a big 2-barrel will get worse mileage than a good vacuum secondary 4-barrel. I had to prove it to myself several years ago. I sure wanted that 2-barrel to win the mileage race, but it didn't.

68Timber · 02-15-2011, 08:55 PM

If you have the stock Q-jet, get it rebuilt by someone who knows what they're doing - mail it off if you have to.

83burban · 02-15-2011, 11:26 PM

A quadrajet acts just like a 2 barrel until you get into the throttle. Have it rebuilt by someone who knows quadrajets or send it to someone who does.

They can set it up to run very efficiently if you give them all the info for your truck and they know what they are doing.

My sub scores 22 mpg when I draft, 15 highway non draft, and 9 in the city. It also have the jets drilled and different rods and hangers to match the cam and the power output I wanted.

4pilgrim4 · 03-04-2011, 11:28 PM

How about a small 500 cfm Edelbrock?

Wouldn't it be equivalent in economy to a Q-jet when operating in the primaries?

Or is there something magic about a Q-jet?

02-13-2011, 08:45 PM	#1
american revolution Registered User Join Date: Apr 2007 Location: san francisco Posts: 446	4 barrel carb to a 2bbl carb have an 80 blazer that i use for a daily driver...4bbl carb on it that needs to get rebuilt soon...with the gas prices here in california (saying it might go as high as $4.50-5.00 per gallon by summer) thinking about changing to a 2bbl carb set up. any negative issues with this?

02-15-2011, 09:12 AM	#2
BigBlocksRule Registered User Join Date: Jun 2008 Location: Lubbock, TX Posts: 2,047	Re: 4 barrel carb to a 2bbl carb Yeah, a big 2-barrel will get worse mileage than a good vacuum secondary 4-barrel. I had to prove it to myself several years ago. I sure wanted that 2-barrel to win the mileage race, but it didn't.

02-15-2011, 08:55 PM	#3
68Timber I know the pieces fit Join Date: Nov 2007 Location: MONTGOMERY, AL Posts: 5,523	Re: 4 barrel carb to a 2bbl carb If you have the stock Q-jet, get it rebuilt by someone who knows what they're doing - mail it off if you have to. __________________ John 79 2wd Blazer (Bruiser) 85 M1009 Blazer (Sarge) build 74 Honda Z50 build

02-15-2011, 11:26 PM	#4
83burban Registered User Join Date: Feb 2008 Location: la Posts: 345	Re: 4 barrel carb to a 2bbl carb A quadrajet acts just like a 2 barrel until you get into the throttle. Have it rebuilt by someone who knows quadrajets or send it to someone who does. They can set it up to run very efficiently if you give them all the info for your truck and they know what they are doing. My sub scores 22 mpg when I draft, 15 highway non draft, and 9 in the city. It also have the jets drilled and different rods and hangers to match the cam and the power output I wanted.

03-04-2011, 11:28 PM	#5
4pilgrim4 Registered User Join Date: Jan 2011 Location: Silverdale, WA Posts: 59	Re: 4 barrel carb to a 2bbl carb How about a small 500 cfm Edelbrock? Wouldn't it be equivalent in economy to a Q-jet when operating in the primaries? Or is there something magic about a Q-jet?



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