Quadrajet Primary Shaft Bushings

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,457
Reaction score
5,609
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
So here is one mod I like and I got the idea from a rebuild kit I had seen.
The float seat had been slotted to assist in fuel flow.
So I cross drill mine, unless the rebuild kit comes with a modified seat.
The windowed seat does allow more flow, which is good for performance builds, but the downside is it can allow the bowl to drain back more and therefore is not recommended for stockish street builds. If everything is tight and working right, it isn't really a concern, but if you have the windowed seat you should really have the rubber one-way valve in the carb filter as well.
 

hey mister

Full Access Member
Joined
Jun 15, 2024
Posts
260
Reaction score
621
Location
North Coast
First Name
Marty
Truck Year
1978
Truck Model
C10
Engine Size
350
.007 clearance? OK so what happened ? Why was there so much clearance with the new bushings and shaft? Was the shaft worn junk? How did you fix that? New shaft available :think:

Every seen that video of, Jeff Bradshaw of Elderly Iron, rapping and tying thread around a Carburetor shaft to fix loose shaft vacuum leak?:eek::eek:
So, I'm not a fan of boobtube.
In a number of "how too" videos, I've seen them intentionally give information that was sure to sabatoge the outcome.

There is biased motivations to maintain subscription numbers and many (not all) tubers are willing to say or do anything to sustain those numbers.

There is no accountability to giving out bad info.
If a project gets scrapped, there is no recourse.
Worse yet, if someone gets hurt, who can you blame?

Again, not all are like this, but they are out there.

The other issue is the people looking to get free info and fix "whatever" on the cheap.

This is why, you will rarely, if ever mention any boobtube.

The best policy is to grab a book of a well renouned author and do your homework.
 

hey mister

Full Access Member
Joined
Jun 15, 2024
Posts
260
Reaction score
621
Location
North Coast
First Name
Marty
Truck Year
1978
Truck Model
C10
Engine Size
350
The windowed seat does allow more flow, which is good for performance builds, but the downside is it can allow the bowl to drain back more and therefore is not recommended for stockish street builds. If everything is tight and working right, it isn't really a concern, but if you have the windowed seat you should really have the rubber one-way valve in the carb filter as well.
Interesting..
How can fuel "drain" back?
Fuel would have to flow against the fuel pump.
 

YakkoWarner

Full Access Member
Joined
May 29, 2024
Posts
181
Reaction score
223
Location
Central Texas
First Name
Wolf
Truck Year
1989
Truck Model
R2500 Suburban
Engine Size
454
From what I can tell from pictures, there seem to be enuf meat to install bushings on the SU's.
The real issue would be, are there bushings availavle from a bearing waerhouse.
I did see a SzU carb on fleabay for $45.

Moss Motors sells a kit with the bushings and a reamer, so I know they parts are available - just their kit is pricey and I'm not sure I could pull it off successfully without actual machining tools. If I can find spares, you may be getting a call (I have no doubt you have the skill and tooling to get it right the 1st time, but I don't want to send off my ONLY pair of SU's or my only throttle body and have them get lost in shipping somewhere, plus I can't really have my Suburban down for however long it takes UPS to get it back and forth).
 

JD Miller

Full Access Member
Joined
Sep 30, 2024
Posts
292
Reaction score
531
Location
Goober Idaho
First Name
JD
Truck Year
1981
Truck Model
K20 silverado
Engine Size
350
Yes, the .007 was prior to installing the new bushings.
OOPS! :idiot:I read it wrong



Take it easy..... Ol' Jeff Bradshaw of Elderly Iron (Redneck Restoration) isnt a "how to" videos. Its was just fun Entertainment Redneck Style, far as Im concerned.
 
Last edited:

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,457
Reaction score
5,609
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Interesting..
How can fuel "drain" back?
Fuel would have to flow against the fuel pump.
Gravity...

If there is any little bit of a leak on the check valve in the pump, it will siphon the fuel right down to the air break point in the fuel bowl. So if you have the full height solid seat, that amount is the full seat height. If you have windowed it, now that amount is all the way to the bottom of those windows. You never notice the amount in the fuel lines being siphoned down because by the time the engine has run long enough to use up all the fuel in the bowl, it has pumped the fuel lines back full and started filling the fuel bowl back up. If you find yourself having to crank the engine for an extended period before it starts after sitting for any amount of time, this is likely what is happening.
 

Latest posts

Forum statistics

Threads
44,337
Posts
954,688
Members
36,566
Latest member
Jugulator
Top