How do i know what kind of carb i have. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BoeJaker1976 · 02-08-2009, 02:04 PM

So about a year ago, my old carberator took a dump and i went to orielys autoparts bought a new one. Its a quadrajet of some sort that looks different than the old one. So what numbers do i need to identify what kind of qjet i have. Since it has been cold my truck has had a hard time starting up and i want to tune it with the chiltons book, but i had no idea that there were a ton of different models.

sierra4x4 · 02-08-2009, 02:29 PM

find the carb # it is located verticaly above the secondary throttle shaft on the drivers side af the carb.

BoeJaker1976 · 02-08-2009, 02:44 PM

ok here are the numbers off the carb

17058213
2647BJB

James McClure · 02-08-2009, 03:38 PM

Bo, the number you want is the 17058213 number. If it's a new carb and the only trouble you are haveing is at startup chances are real good you only have a choke setting problem. Take the air cleaner off, open the throttle better than 1/2 way and let it close again. The choke plate should be closed and if you push down on the front side of the plate yu should feel a bit of resistance. Start the eng and see that the choke has opened about 1/4". If it has the start problem may not be the carb. If it dosen't open either the pull off is bad or not connected to a vac source. The manual can walk you thru adjustments if you find them to be wrong. jim

BoeJaker1976 · 02-08-2009, 03:43 PM

ok cool. but what kind of carburetor is it?

James McClure · 02-08-2009, 03:59 PM

Qjet came in so many different flavors it's hard to say exactly which one it is. Just make sure when you bought it that it matches the application. The PO may have swaped carbs at one time and not used the right one, so the right one looks wrong, OR, the motor is a swap out but a different year. Check the numbers on the block on the tab that sticks out in front of the right cyl head and have GM tell you what the motor is and it's year. There might be someone here who can tell you. I dn't know the numbers myself. jim

sierra4x4 · 02-08-2009, 04:12 PM

The carb you hae is a rochester quadrajet #17058213 which is for a 1978 chevrolet truck 350 4 barrel heavy duty. So it should work fine for your application, but their may be many internal differances between it and yor original carb(eg. jets,metering rods ect.) It would be best to get the same number carb as your original carb.

BoeJaker1976 · 02-08-2009, 04:33 PM

ok. going through the chilton book i see things like 4mv m4mmc and things like that, how do i find out which one of these it is?

dswancutt · 02-08-2009, 04:38 PM

Here is a link to decode your carb numbers. I also recomend them as a source for rebuilt carbs.

http://www.carburetion.com/quadnumber.htm

Here is how your carb number plays out

17058213

1705 - 1976-79
8 - year built 1978
2 - carb type - 2 = quadrajet
1- car model - 1 = Chevy
3 - transmission type - odd = manual, even = automatic

The second number you listed did not check out.

02-08-2009, 02:29 PM	#2
sierra4x4 Registered User Join Date: Jan 2009 Location: Canada Posts: 308	Re: How do i know what kind of carb do i have. find the carb # it is located verticaly above the secondary throttle shaft on the drivers side af the carb.

02-08-2009, 02:44 PM	#3
BoeJaker1976 Registered User Join Date: May 2005 Location: copperas Cove, TX Posts: 85	Re: How do i know what kind of carb do i have. ok here are the numbers off the carb 17058213 2647BJB __________________ 1976 Red chevy steppy, Proud service member, US ARMY 15Y, AH-64D Apache Longbow Armament, Avionics, Electronics technician

02-08-2009, 03:38 PM	#4
James McClure One shot, one kill. Join Date: Dec 2007 Location: Saratoga Springs NY Posts: 859	Re: How do i know what kind of carb do i have. Bo, the number you want is the 17058213 number. If it's a new carb and the only trouble you are haveing is at startup chances are real good you only have a choke setting problem. Take the air cleaner off, open the throttle better than 1/2 way and let it close again. The choke plate should be closed and if you push down on the front side of the plate yu should feel a bit of resistance. Start the eng and see that the choke has opened about 1/4". If it has the start problem may not be the carb. If it dosen't open either the pull off is bad or not connected to a vac source. The manual can walk you thru adjustments if you find them to be wrong. jim __________________ 1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.

02-08-2009, 03:43 PM	#5
BoeJaker1976 Registered User Join Date: May 2005 Location: copperas Cove, TX Posts: 85	Re: How do i know what kind of carb do i have. ok cool. but what kind of carburetor is it? __________________ 1976 Red chevy steppy, Proud service member, US ARMY 15Y, AH-64D Apache Longbow Armament, Avionics, Electronics technician

02-08-2009, 03:59 PM	#6
James McClure One shot, one kill. Join Date: Dec 2007 Location: Saratoga Springs NY Posts: 859	Re: How do i know what kind of carb do i have. Qjet came in so many different flavors it's hard to say exactly which one it is. Just make sure when you bought it that it matches the application. The PO may have swaped carbs at one time and not used the right one, so the right one looks wrong, OR, the motor is a swap out but a different year. Check the numbers on the block on the tab that sticks out in front of the right cyl head and have GM tell you what the motor is and it's year. There might be someone here who can tell you. I dn't know the numbers myself. jim __________________ 1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.

02-08-2009, 02:04 PM	#1
BoeJaker1976 Registered User Join Date: May 2005 Location: copperas Cove, TX Posts: 85	How do i know what kind of carb i have. So about a year ago, my old carberator took a dump and i went to orielys autoparts bought a new one. Its a quadrajet of some sort that looks different than the old one. So what numbers do i need to identify what kind of qjet i have. Since it has been cold my truck has had a hard time starting up and i want to tune it with the chiltons book, but i had no idea that there were a ton of different models. __________________ 1976 Red chevy steppy, Proud service member, US ARMY 15Y, AH-64D Apache Longbow Armament, Avionics, Electronics technician

02-08-2009, 04:12 PM	#7
sierra4x4 Registered User Join Date: Jan 2009 Location: Canada Posts: 308	Re: How do i know what kind of carb do i have. The carb you hae is a rochester quadrajet #17058213 which is for a 1978 chevrolet truck 350 4 barrel heavy duty. So it should work fine for your application, but their may be many internal differances between it and yor original carb(eg. jets,metering rods ect.) It would be best to get the same number carb as your original carb.

02-08-2009, 04:33 PM	#8
BoeJaker1976 Registered User Join Date: May 2005 Location: copperas Cove, TX Posts: 85	Re: How do i know what kind of carb do i have. ok. going through the chilton book i see things like 4mv m4mmc and things like that, how do i find out which one of these it is? __________________ 1976 Red chevy steppy, Proud service member, US ARMY 15Y, AH-64D Apache Longbow Armament, Avionics, Electronics technician

02-08-2009, 04:38 PM	#9
dswancutt Registered User Join Date: Jul 2003 Location: Franklin, NE Posts: 387	Re: How do i know what kind of carb do i have. Here is a link to decode your carb numbers. I also recomend them as a source for rebuilt carbs. http://www.carburetion.com/quadnumber.htm Here is how your carb number plays out 17058213 1705 - 1976-79 8 - year built 1978 2 - carb type - 2 = quadrajet 1- car model - 1 = Chevy 3 - transmission type - odd = manual, even = automatic The second number you listed did not check out. Last edited by dswancutt; 02-08-2009 at 04:38 PM.



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