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Holley Carb replacement suggestions

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Holley Carb replacement suggestions

Posted: 5/20/22 8:02pmMessage 1 of 11
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Milford, DE - USA
Joined: 11/6/2021
Posts: 67
Vette(s): 1977 C3 Auto Coupe Lt Blue/Dk Blue Prev. 1968 C3 convertible 4spd Red 1984 C4 Automatic Silver 2000 C5 Automatic Black

I would like to know what Holley Carb. would bolt right on my all stock L48 auto with air. It has Vacumn secondary and electric choke. I assume its a spreadbore because of the stock looking manifold. It has a Holley( see pic) on it now but it's over 22 years old and probaby better to just replace it. Any ideas on a perfect replacement? 

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Re: Holley Carb replacement suggestions

Posted: 5/20/22 8:15pmMessage 2 of 11
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Grapevine, TX - USA
Joined: 8/26/2006
Posts: 1537
Vette(s): 1972 LT-1 convertible with factory air. 2017 Black Rose Grand Sport M7 convertible.

I put a Holley Street Avenger 670 on my LT-1. 

   

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Re: Holley Carb replacement suggestions

Posted: 5/21/22 9:50amMessage 3 of 11
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Milford, DE - USA
Joined: 11/6/2021
Posts: 67
Vette(s): 1977 C3 Auto Coupe Lt Blue/Dk Blue Prev. 1968 C3 convertible 4spd Red 1984 C4 Automatic Silver 2000 C5 Automatic Black

Thanks for the info. I don't think thats a spreadbore carb. If I used that I would need a adapter plate?

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Re: Holley Carb replacement suggestions

Posted: 5/21/22 11:59amMessage 4 of 11
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Waterford, MI - USA
Joined: 9/13/2002
Posts: 1795
Vette(s): 1973 Red coupe

I replaced my Q-jet with a Holly 4175 spreadbore

i can’t believe how the cost have gone up on these

bought mine at Summit 

https://www.summitracing.com/parts/hly-0-80555c



|UPDATED|5/21/2022 11:59:33 AM (AZT)|/UPDATED|

Brian - NCM Lifetime Member

73 coupe L48, Flat-top pistons, Performer RPM Heads, Crane Cam and roller rockers, Holley 650 vac sec. Performer intake,
3.55 gear BTO 200-4R trans,
Leather seats, Seatbelt Plus 3point seatbelts, Pioneer CD player
Magnaflow Exhuast System

Dewitt radiator and dual electric fans
Borgeson Steering box
 


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Re: Holley Carb replacement suggestions

Posted: 5/21/22 2:36pmMessage 5 of 11
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Milford, DE - USA
Joined: 11/6/2021
Posts: 67
Vette(s): 1977 C3 Auto Coupe Lt Blue/Dk Blue Prev. 1968 C3 convertible 4spd Red 1984 C4 Automatic Silver 2000 C5 Automatic Black

Yeah thats crazy..Thinking about changing manifold to Edelbrock and do away with the spreadbore.

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Re: Holley Carb replacement suggestions

Posted: 5/21/22 5:43pmMessage 6 of 11
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Burke, VT - USA
Joined: 1/23/2002
Posts: 7601
Vette(s):
SOLD - "The Toy" - '70 Convertible
SOLD - "The Beast" - '90 ZR-1 (#682)
SOLD - "Betty" - '28 Ford Model A Tudor
SOLD - "BLKBRRD" - '78 Pontiac Trans Am
"BLUBYU" - '04 Coupe

A spread bore actually is a good carb.  With the primaries being smaller they sip a little less fuel when cruising.  And the larger secondaries add a punch when you mash the go pedal.

Jim Olson 

"The Toys"...!!!  Save the Wave!

Where I've been in a Corvette...!!!

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Re: Holley Carb replacement suggestions

Posted: 5/21/22 6:04pmMessage 7 of 11
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Milford, DE - USA
Joined: 11/6/2021
Posts: 67
Vette(s): 1977 C3 Auto Coupe Lt Blue/Dk Blue Prev. 1968 C3 convertible 4spd Red 1984 C4 Automatic Silver 2000 C5 Automatic Black

Just can't believe the prices on them..I've seen anywhere from $657.00 to $900.00 for the exact same carb! 

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Re: Holley Carb replacement suggestions

Posted: 5/22/22 9:37amMessage 8 of 11
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Overland Park, KS - USA
Joined: 7/9/2003
Posts: 916
Vette(s): 1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day. 2023 Accelerate Yellow HTC Stingray

Your cheapest option would be to rebuild your existing spreadbore. The next option that I would entertain would be to get a good Q-jet and put on it.

1973 L-82 4 spd

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Re: Holley Carb replacement suggestions

Posted: 5/22/22 1:52pmMessage 9 of 11
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Milford, DE - USA
Joined: 11/6/2021
Posts: 67
Vette(s): 1977 C3 Auto Coupe Lt Blue/Dk Blue Prev. 1968 C3 convertible 4spd Red 1984 C4 Automatic Silver 2000 C5 Automatic Black

I was thinking about rebuilding it but it's aleast 20+ years old. 

Rather just get something newer. Open to the Q-Jet idea however they're just as old.






|UPDATED|5/22/2022 1:52:01 PM (AZT)|/UPDATED|
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Re: Holley Carb replacement suggestions

Posted: 5/23/22 9:59amMessage 10 of 11
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Overland Park, KS - USA
Joined: 7/9/2003
Posts: 916
Vette(s): 1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day. 2023 Accelerate Yellow HTC Stingray

Mine's almost 50 years old and I'm getting ready to rebuild it again. Check out Cliff Ruggles book on Q-jets on how to rebuild and modify them. He also sells the rebuild kit for a reasonable amount of money.

The only thing I remember about a Holley Spreadbore is that I had a friend back in the seventies that put one on his '72 and not too long afterwards, put his Q-jet back on.

1973 L-82 4 spd

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