Carb Swap?

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.

GTX63

Full Access Member
Joined
Nov 27, 2022
Posts
957
Reaction score
3,898
Location
Tennessee
First Name
Ty
Truck Year
1985
Truck Model
K10
Engine Size
350
I had never seen a spread bore on a stock GM that's why I asked. If vehicle runs good with it that's great but I wouldn't toss the original Q jet away.

As a young kid in 1984, I bought a 1965 Chevy Caprice off the original owners. They had seen the car inside a Chevrolet dealership showroom and wanted it. The salesman said it was a display only and the first one they received with a 396 (replacing the 409). They said sell it or no sale, so the dealership did the deal.
Anyway, it was a factory 325HP 396, with a GM stamped Holley carb, oval port heads but a solid lifter cam. In other words, GM hadn't sorted out the specs completely yet, or had all the correct parts available, and mixed it with high end components. I don't recall now, but I had traced the numbers and codes and the engine was one of the first 100 produced and literally weeks after the introduction. The motor was tired, sucked gas and needed more work than I was capable of, but it was a fun car and of course, worth a lot more now than I can imagine.
 

fast 99

Full Access Member
Joined
Dec 31, 2021
Posts
2,095
Reaction score
3,075
Location
Spokane, Washington
First Name
Brian
Truck Year
81,85
Truck Model
K20
Engine Size
350
As a young kid in 1984, I bought a 1965 Chevy Caprice off the original owners. They had seen the car inside a Chevrolet dealership showroom and wanted it. The salesman said it was a display only and the first one they received with a 396 (replacing the 409). They said sell it or no sale, so the dealership did the deal.
Anyway, it was a factory 325HP 396, with a GM stamped Holley carb, oval port heads but a solid lifter cam. In other words, GM hadn't sorted out the specs completely yet, or had all the correct parts available, and mixed it with high end components. I don't recall now, but I had traced the numbers and codes and the engine was one of the first 100 produced and literally weeks after the introduction. The motor was tired, sucked gas and needed more work than I was capable of, but it was a fun car and of course, worth a lot more now than I can imagine.
Scrapped 100's and 100's of vehicles from the mid 70's until early 2000's. If I could remember what they were probably cry for a week. Give you an example of one I remember because sold it to a friend. Was a 65 Chevelle convert about 1976 or 77 $250.

Anyway, back the Holley subject. Know GM installed Holley's from the factory. Was referring in particular to the spread bore.
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,756
Reaction score
11,422
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
I paid a little over 300 for a stage 2 quadrajet from national carburetors in Florida. Stage 2 is fir a motor with cam, intake and hedders. They tune it for you so it's ready to go right out the box. That guy will save you about 100 bucks to rebuild it. Score!
National is good stuff. There are no carb shops left in my area, I'm good at doing them and know the Q-jet pretty well but if a carb has bad throttle plate bushings, I have no way to fix that, so that is when we call National Carburetor. Or sometimes O'Reilly's as O'Reilly's is a distributor for National and can sometimes get it to us a little faster. But I always prefer doing business with National directly as I know the carb hasn't been sitting on a shelf upside down for decade, which could happen at O'reilly's.
 

Matt69olds

Full Access Member
Joined
Jan 8, 2018
Posts
2,487
Reaction score
3,900
Location
Central Indiana
First Name
Matt
Truck Year
81
Truck Model
GMC 1/2 ton
Engine Size
455 Olds
The Qjet was the factory go to 4 barrel on GMs for 20+ years for a reason. Believe it or not, brand new they used to start with little more than a turn of the key and a single pump on the pedal. I buy my rebuild kits from Quadrajetpower.com.
Edelbrocks are popular replacements because they are ready to go out of the box, and well, easier to find that a new Quadrajet. That said, I currently have two in use and they are, to me, a C- substitute.
Qjets are not hard to tune unless the engine has issues or you are trying to do it flying by the seat of your pants.
Understanding the mixture screw adjustments, setting the idle, using the lean drop method, etc are not hard concepts if you learn the steps and procedures correctly from the start.
Try closer to 40 years!!

The “good” Q-Jets started in the early 70s, and production ending in 1990.
 

Matt69olds

Full Access Member
Joined
Jan 8, 2018
Posts
2,487
Reaction score
3,900
Location
Central Indiana
First Name
Matt
Truck Year
81
Truck Model
GMC 1/2 ton
Engine Size
455 Olds
The Qjet was the factory go to 4 barrel on GMs for 20+ years for a reason. Believe it or not, brand new they used to start with little more than a turn of the key and a single pump on the pedal. I buy my rebuild kits from Quadrajetpower.com.
Edelbrocks are popular replacements because they are ready to go out of the box, and well, easier to find that a new Quadrajet. That said, I currently have two in use and they are, to me, a C- substitute.
Qjets are not hard to tune unless the engine has issues or you are trying to do it flying by the seat of your pants.
Understanding the mixture screw adjustments, setting the idle, using the lean drop method, etc are not hard concepts if you learn the steps and procedures correctly from the start.
Besides people not understanding how they operate, unfortunately you can’t fix decades of wear and tear with a cheap autozone rebuild kit and a can of carb cleaner.

The engine will never run right if the throttle shaft bores are worn out. People never remove the air bleeds to clean out the gunk inside. Then try to bolt a carb from one family onto something completely different and then wonder why it runs like crap.
 

saig55

Junior Member
Joined
Feb 26, 2024
Posts
29
Reaction score
49
Location
Mason, Tn
First Name
Thomas
Truck Year
1986
Truck Model
K10 Silverado
Engine Size
305
I don’t have the expertise… that is why I don’t mind farming some stuff out. This man has been a mechanic for over 50 years… these old smart guys are slowly fading away..
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,624
Reaction score
9,198
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
I don’t have the expertise… that is why I don’t mind farming some stuff out. This man has been a mechanic for over 50 years… these old smart guys are slowly fading away..
Yes, we determined yesterday that @bucket was the last one!!!!
 

82sbshortbed

Fuckemall!!
Joined
Mar 1, 2018
Posts
15,981
Reaction score
53,856
Location
SE Texas
First Name
Doug
Truck Year
1982, 1984
Truck Model
1500 shortbed, 1500 longbed
Engine Size
454, 305
National is good stuff. There are no carb shops left in my area, I'm good at doing them and know the Q-jet pretty well but if a carb has bad throttle plate bushings, I have no way to fix that, so that is when we call National Carburetor. Or sometimes O'Reilly's as O'Reilly's is a distributor for National and can sometimes get it to us a little faster. But I always prefer doing business with National directly as I know the carb hasn't been sitting on a shelf upside down for decade, which could happen at O'reilly's.
Yeah they're great! I called them when looking for a quadrajet. He was very helpful and asked what I was planning to do to the engine. I told him a cam, intake and hedders. That's when he recommended that one and I've been really happy with it. I was thinking about getting another one for the 84 to replace the edelbrock on there. If I do ill get it from them.
 

Finkaire

Finkaire
Joined
Dec 28, 2021
Posts
454
Reaction score
747
Location
California
First Name
Loren
Truck Year
1984
Truck Model
Silverado c10
Engine Size
305
Quad gone through, happy happy happy
 

mtbadbob

Full Access Member
Joined
May 9, 2021
Posts
668
Reaction score
1,048
Location
Montana
First Name
Bob
Truck Year
1987
Truck Model
V20
Engine Size
350
Try closer to 40 years!!

The “good” Q-Jets started in the early 70s, and production ending in 1990.
The W-30 7040256 & 258'S are like gold bars these days!
 

potent rodent

Full Access Member
Joined
Mar 22, 2020
Posts
195
Reaction score
112
Location
indiana
First Name
butch
Truck Year
86 and 78
Truck Model
1500
Engine Size
350 and 305
i like the quadrajet good fuel milage , also the holley spread bore good milage till u put your foot into it
 

saig55

Junior Member
Joined
Feb 26, 2024
Posts
29
Reaction score
49
Location
Mason, Tn
First Name
Thomas
Truck Year
1986
Truck Model
K10 Silverado
Engine Size
305
Got it back and he said it had never been apart. Looked new on the inside..
Weekend project…
Does anybody have a picture or something to show me how all the linkage hooks up.. I believe my transmission linkage is not hooked up right now
 

Latest posts

Forum statistics

Threads
44,435
Posts
957,907
Members
36,803
Latest member
haskelled53
Top