Hello!

I am looking for information, advice, recommendations and help. I am swapping my 4V Holley back to a 4V Quadrajet. I do not know carburetors well. I know the theory but not so much practical application. Please don’t just tell me to check the service manual. Nothing I have is stock so the manual does not help much. Here’s is what I have.

1976 SBO 350 casting 395558 2
Edelbrock Performer 350 intake
19?? HEI OEM distributor
19?? BOP 350 Turbo Hydromatic, downshift cable connected to the carb
Holley 4V carburetor, manual choke – open full time.
No EGR
No air cleaner vacuum requirements.
No choke stove/hot air setup
No a/c

Right now the vacuum lines are connected a follows.

Power brakes booster plumbed to intake
PCV is drawn into the carb
Distributor vacuum advance tee-ed to manifold vacuum on carb
350THydromatic modulator tee-ed to manifold vacuum on carb

I have a 1972 455 7042251 recently rebuilt carb that was on a running 403 in a late 70’s Firebird.
I have a new Quadrajet carb spacer/insulator and mounting kit.
I have a new fuel pump to carb stainless steel fuel line.

What I am not sure of is where I need to connect the vacuum lines and what to cap off if unused.

My quadrajet does not have any throttle cable brackets. I am hoping that one being used with the Holley will work. It is anchored on the rear driver side mounting stud for the carb. My throttle cable had an open eye/hole to connect the carb. This looks like it should fit on the quadrajet.




Top cable is the throttle and the bottom one with the blue overspray is the downshift cable that goes to transmission. The bracket is mounted on the driver side rear carb stud.

The quadrajet has similar linkage. I hope I can still connect the downshift to the linkage on the carb.

I need help with the choke setup. Currently my Holley is manual choke which is never moved. The Quadrajet has the internal vacuum choke. I do not have a choke heat pipe. Do I need to get a setup to mount on the Edelbrock intake or do I have options besides the electric choke kit.



To use a heat pipe should I be placing it where the cover plate is? This picture show the one vacuum line used on my current setup. It is tee-ed to the distributor and 350 th transmission.

Here are the four sides of my quadra jet.



The choke heat pipe assembly should go here. What are my options since I do not have that setup. Buy? Electric? Plug and ignore?



A PCV valve.
B
C
* What goes here? Are these for mounting brackets?
B or C would be where I current have the two lines tee-ed off of.



What should connect to the drivers/passengers side nipple. Does the choke heat pipe connect to the passenger side?



My downshift cable should be able to mount to the throttle linkage on the bottom, correct?

Thanks for any help you can provide. I would also like to know if on a mildly built 350 should a be using ported or manifold vacuum for the distributer/transmission.


Adam

 

I can not believe I have you all stumped. Kudos to me. I know the site was slow yesterday. I hope you were all out drive the Olds instead or surfing them.

Adam

 

I'll be watching since I have almost the same setup as you now and someday want to swap to a Q-jet. Always assumed an electric choke on a Q-Jet would be easiest since my Holley has that and the choke tube is capped on the intake.

 

Generally, long posts get less replies, IMO. On the choke, go to the boneyard and snag an electric choke, many trucks will have them. Then cap off the carb. Then run to 12 volts with ignition "on". Easy, cheap, and works better than hot air.

There should be a vacuum port near the rear passanger side of the intake for the modulator (trans) vacuum. edit, I actually see it in your pic, so it is there.

"B" is manifold vacuum, "C" is probably ported vacuum. They are used for various things, emissions, etc, usually hooked to temp switches for timing and idle controls. See if you can locate a diagram.

Linkage issues can be tough over the internet, especially with mis-matched parts.