quadrajet differences? - Off-Road Forums & Discussion Groups
GM Standard SFA Trucks & SUV's All discussion of full sized Solid Front Axle Trucks, SUV's to include Suburban

 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 04-12-2002, 01:28 PM
**DONOTDELETE**
Guest
 
Posts: n/a
quadrajet differences?

I put my new 400sbc in last week and an curios about carbs. I ran for a week with the original carb from teh 400 and it worked ok but last night I put the one on from the 305 and it seems deader now but teh 305 carb has all teh electrical stuff on it. Is there any difference between carbs on a '75 400 vs a '86 305 besides electrical stuff? Is one bigger than the other. Both are quadrajets
Sponsored Links
Advertisement
 
post #2 of (permalink) Old 04-12-2002, 07:26 PM
 
Join Date: Feb 2002
Posts: 41
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: quadrajet differences?

I don't know the specifics, but I am fairly sure the newer carb is jetted differently. I ran into the same problem not too long ago. Picked up a pro-rebuilt Q-jet for a 305, put it on my new 350 and it ran so rich I was fouling plugs. Took the carb to the rebuild shop told them the problem and the guy said he rejetted it for an older 350, now it works GREAT!!! If you are not a carb guy, like me, I would take it to a rebuild shop and have them go through it for your specific engine.
ike73 is offline  
post #3 of (permalink) Old 04-12-2002, 09:49 PM
Keyboard Implanted
 
dave's Avatar
 
Join Date: Sep 1999
Location: Vancouver, Washingon
Posts: 2,346
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: quadrajet differences?

There are 4 basic types of quadrajets. Usually the choke type determines what type the quardajet is. Older quadrajets use a bi-metal spring for the choke, usually 68 - 74 quadrajets have this type choke. Next on the list of choke types are the heat raiser tube type chokes, which have a tube going to the intake manifold to the quadrajet choke housing. Usually the heat raiser tube type chokes are from 74 - 79. Next on the list of choke types are the electric chokes, which have an electric wire going to the choke element. Usually the 80 - 86 quardajets have electric choke.

Now for the real fun, there are two types of electronic quadrajets. One type used a computer to control a mixture control solenoid, often called the feedback system. The other type of electronic quadrajet never had a computer, but used a temperature switch in the intake manifold for a choke enrichment solenoid. Usually the choke enrichment solenoid type quadrajet was used on pickups with the Electronic Spark Control (ESC) system.

Heck yes, there are different types of quadrajets! [img]images/icons/smile.gif[/img]
dave
dave is offline  
Sponsored Links
Advertisement
 
post #4 of (permalink) Old 04-15-2002, 08:58 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: quadrajet differences?

wow, all the possibilities. The 400 carb had the choke with the spring in teh intake. It is a '76 motor. The 305 has an electric choke and a few electrical ports and a port to the fuel canister emissions thaing that was removed. I think what I will do is put teh 400 carb back on it then get a manual lockup kit for my 700R4. Thanks for the help.
post #5 of (permalink) Old 04-15-2002, 01:52 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: quadrajet differences?

Does anyone know if an electric choke conversion available for Q-jets with the bi-metallic spring setup?
post #6 of (permalink) Old 04-15-2002, 06:43 PM
Keyboard Implanted
 
dave's Avatar
 
Join Date: Sep 1999
Location: Vancouver, Washingon
Posts: 2,346
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: quadrajet differences?

Sorry Quack_Addict,[img]images/icons/frown.gif[/img] the bi-metal spring type choke quadrajet can not be converted to an electric using factory parts.
dave
dave is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome