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| Is this carb useful [message #362781] |
Fri, 12 March 2021 16:20  |
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Tom Lins
Messages: 372
Registered: February 2004
Location: St Augustine, FL
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Is a Quadrajet with part number 7043254RL useful for a 455?
Tom Lins
St Augustine, FL
77 GM Rear Twin, Dry Bath, 455, Aluminum Radiator Quad-Bag Suspension Solar Panel
Manuals on DVD
YOUTUBE Channel: GMC Dealer Training Tapes
http://www.bdub.net/tomlins/
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| Re: Is this carb useful [message #362784 is a reply to message #362781] |
Fri, 12 March 2021 19:58  |
C Boyd
Messages: 2629
Registered: April 2006
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Sir, it depends on which 455 and what you are using it for. If you would look at the carb and see if it has a primary metering rod and power piston in it. If it doesn’t it is great for max acceleration in a 1/4 mile but not so good for mpg. The book lists it for a 73 w-31 or w-30 application probably out of a 442 with automatic transmission.
Tom Lins wrote on Fri, 12 March 2021 17:20Is a Quadrajet with part number 7043254RL useful for a 455?
C. Boyd
76 Crestmont
East Tennessee
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| Re: Is this carb useful [message #362786 is a reply to message #362781] |
Fri, 12 March 2021 21:31 |
Rick Staples
Messages: 126
Registered: May 2014
Location: Johnstown, Colorado, USA
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The 7043254 carburetor was original equipment for 1973, '74, and very early '75 GMCs with the 455 engine. It is what I have in my early '75 Eleganza, built in Nov. '74. Don't know about the letters stamped after the part number, but Cliff Ruggles' excellent book "How to Rebuild and Modify Rochester Quadrajet Carburetors" (cartechbooks.com) says that Rochester used two or three letters to designate the factory which produced the carb. So I believe yes, this carb is very useful, unless you have a late California GMC.
My 2¢, HTH
Rick Staples
Rick Staples, '75 Eleganza, Johnstown, CO
"Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien
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| Re: Is this carb useful [message #362788 is a reply to message #362781] |
Fri, 12 March 2021 22:16 |
blur911
Messages: 166
Registered: December 2020
Location: Kingston, Ontario
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A friend is selling a new, never used, Quadrajet 7043240 for $450CAD. Is this useful or a good price?
Burl Vibert
Kingston, Ontario
1976 GMC 26 foot, Sheridan reno, don't know original model but we call her Roxie
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| [GMCnet] Re: Is this carb useful [message #362792 is a reply to message #362788] |
Sat, 13 March 2021 16:36 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
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I've heard Dick Paterson say that he's had no success in adapting other
carbs to the GMC, even using Toronado cores, replacing jets and metering
rods with those from GMCs, etc. If Dick can't do it, with his flow bench
and extensive experience, I doubt anyone can.
Ken H.
On Fri, Mar 12, 2021 at 11:16 PM Burl Vibert wrote:
> A friend is selling a new, never used, Quadrajet 7043240 for $450CAD. Is
> this useful or a good price?
> --
> Burl Vibert
> Kingston, Ontario
> 1976 GMC 26 foot, don't know the model
> _______________________________________________
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Is this carb useful [message #362794 is a reply to message #362790] |
Sat, 13 March 2021 19:54 |
blur911
Messages: 166
Registered: December 2020
Location: Kingston, Ontario
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kingd wrote on Sat, 13 March 2021 12:56Burl, after reading LOTS on the GMCMH forum this is what I think I know about QUADRAJETS and GMC
motorhomes.
I think the carbs used on the motorhomes from the factory were unique to the motorhomes.
There are 455 carbs and 403 carbs. There is some variance across the years There are California and
"Federal" carbs.
It appears the carb your friend has is originally off a BUICK
https://quadrajetpower.com/buick-1973-800-cfm-455-divorced-choke-quadrajet-7043240/
Ahhh, his ad mentioned 455, but not which one. Haven't spoken to him directly. Didn't realize they were so specific.
Burl Vibert
Kingston, Ontario
1976 GMC 26 foot, Sheridan reno, don't know original model but we call her Roxie
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| Re: Is this carb useful [message #362796 is a reply to message #362794] |
Sat, 13 March 2021 21:39 |
Rick Staples
Messages: 126
Registered: May 2014
Location: Johnstown, Colorado, USA
Karma: -1
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Back in the late '60s - early '70s, GM had the Pontiac 455, the Buiok 455 and the Oldsmobile 455. All different, few if any parts interchangeable. You might get the Buick carb to work if you're a hot-rod expert, but with its "divorced" choke (bimetal coil mounted on the intake manifold crossover and linked to the carb externally), it has no place to put even an electric choke coil, so you'd have to use a hand choke. Also, the throttle lever is a bit weird, requiring a different return spring setup. I think you can find better options out there.
My 2¢, HTH
Rick Staples
Rick Staples, '75 Eleganza, Johnstown, CO
"Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien
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| [GMCnet] Re: Is this carb useful [message #362797 is a reply to message #362794] |
Sat, 13 March 2021 21:25 |
powwerjon
Messages: 849
Registered: March 2013
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Unless it is a Motorhome carb number: 455 73-76 and very early 77 the number is 7045254. The 77 & 78 403 is part# 17057254 and the 78 403 Calif version is part# 17057559(CA). Theses are the only Carb numbers that will work successfully on the GMC Motorhome. Dick Paterson will only accept these part numbers for trade in and/or rebuild your own. As Ken H said Dick worked for a number of years on his dyno to make them work and couldn’t!! The internals and parts are different between the MH and cars. Sorry to punch a hole in your balloon, but that is life in the GMC MH Lane!
J.R. Wright
GMC Great Laker MHC
GMCGL Tech Editor
GMC Eastern States Charter Member
GMCMI
78 GMC Buskirk 29.5’ Stretch
75 GMC Avion (Under Reconstruction)
Michigan
> 0On Mar 13, 2021, at 8:54 PM, Burl Vibert wrote:
>
> kingd wrote on Sat, 13 March 2021 12:56
>> Burl, after reading LOTS on the GMCMH forum this is what I think I know about QUADRAJETS and GMC
>> motorhomes.
>> I think the carbs used on the motorhomes from the factory were unique to the motorhomes.
>> There are 455 carbs and 403 carbs. There is some variance across the years There are California and
>> "Federal" carbs.
>> It appears the carb your friend has is originally off a BUICK
>> https://quadrajetpower.com/buick-1973-800-cfm-455-divorced-choke-quadrajet-7043240/
>
> Ahhh, his ad mentioned 455, but not which one. Haven't spoken to him directly. Didn't realize they were so specific.
>
> --
> Burl Vibert
> Kingston, Ontario
> 1976 GMC 26 foot, don't know the model
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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| [GMCnet] Re: Is this carb useful [message #362822 is a reply to message #362794] |
Sat, 13 March 2021 20:23 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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GMC Motorhomes are particularly model specific on Carbs.
This is not to say that other model numbers will not make the engine
run. They will, but high speed metering on these coaches is critical. No
other quadrajets are fitted with what the GMC comes with from the factory.
Dick Paterson is the man on these carbs. That, and ignition curves and
distributors as well. You can't go wrong with what he says.
Jim Hupy
Salem, Oregon
On Sat, Mar 13, 2021, 5:55 PM Burl Vibert wrote:
> kingd wrote on Sat, 13 March 2021 12:56
>> Burl, after reading LOTS on the GMCMH forum this is what I think I know
> about QUADRAJETS and GMC
>> motorhomes.
>> I think the carbs used on the motorhomes from the factory were unique to
> the motorhomes.
>> There are 455 carbs and 403 carbs. There is some variance across the
> years There are California and
>> "Federal" carbs.
>> It appears the carb your friend has is originally off a BUICK
>>
> https://quadrajetpower.com/buick-1973-800-cfm-455-divorced-choke-quadrajet-7043240/
>
> Ahhh, his ad mentioned 455, but not which one. Haven't spoken to him
> directly. Didn't realize they were so specific.
>
> --
> Burl Vibert
> Kingston, Ontario
> 1976 GMC 26 foot, don't know the model
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
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