Re: IML: Edelbrock carb change

["Frederick Joslin" <fljoslin@xxxxxxxx>]

Hi Chris:

 

Thermoquads were used from 1972 and later on 360 - 440 engines. Your car would not have one if the carb is original.

Also, I inadvertently gave them an additional 100 cfm. They were actually rated at 795 cfm.

 

I was using this particular carb as an example of "what is the correct carb size" question? 

 

The factory installed 795 cfm carbs on 360 cu inch engines which most people would say is a huge over kill. I am not saying to go out and get an 800 cfm carb, but it is not as simple as just the cfm rating. It is carb specific.

 

If you want a new carb, look to the carb manufacturer for their recommendation for the carb size for your size of engine (440) making the HP (350 ish) that you intend to make.

Alternately, members of the Imperial list have specific aftermarket carbs which they know work well with these cars.  

 

Assuming that your carb is good, you probably need a complete tune-up with an oxygen sensor in the exhaust to really set the carb and timing correctly. 

If you have questions about the carb presently on your car I would get the professional carb rebuild or an aftermarket carb and then get the tune-up.

 

Good luck and sorry for any confusion.

----- Original Message -----
From: "Chris Strohmeyer"
To: mailing-list@xxxxxxxxxxxxxxxx
Subject: Re: IML: Edelbrock carb change
Date: Wed, 17 Jan 2007 15:16:39 -0800

Are you saying mine is a Thermoquad? I rebuilt mine but am having running problems and am considering the rebuild service at Carburetors and more in Phoenix Arizona for 115.00. They say they rebuild and test your carb on a live engine.  Has anyone dealt with them?

Thx,

Chris

67 Imperial Convertible

----- Original Message -----

From: Frederick Joslin

To: mailing-list@xxxxxxxxxxxxxxxx

Sent: Sunday, January 14, 2007 8:31 AM

Subject: Re: IML: Edelbrock carb change

The carb size question is misleading because it depends on the relative size of the primaries vs. the secondaries.

The Thermoquad carbs had very large secondaries relative to the primaries. I believe that they were  typically rated at 895 CFM, but most of that was through the secondaries which are not used in "normal" driving.

----- Original Message -----
From: "Klebert L. Hall"
To: mailing-list@xxxxxxxxxxxxxxxx
Subject: Re: IML: Edelbrock carb change
Date: Sun, 14 Jan 2007 10:45:56 -0500


> From: "Chris Strohmeyer"
> Subject: IML: Edelbrock Carb change
>
> Hi all,
>
> I've had VERY good luck on my 64 Dart with a new Edelbrock 650cfm about 10
> years ago. I'm considering one for my 67 Imperial 440 to replace the AFB.
> What CFM would you recommend? And do the electric chokes work well and how
> do they work?
> I'd like the car to run as well as possible so if more or less fuel will
> help then fine.

I have an Edelbrock AVS-clone with electric
choke on my '69. Works great, even though the
jets aren't quite right.
All it 'needs' is a 650, which is about what
the factory unit was. If you want more high-rpm
hp, then you might want a bigger carb. If it
has the HP cam or something like it, a 780 is
what's reccommended around these parts.
My understanding is that (for some reason I
don't get) the bigger carbs boost your high-end
horsepower, but hurt your low-end torque (at
least unless you change other stuff too), so
you might not want bigger.

-Kle.
'69 Crown 4DHT -----------------
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Fred Joslin

Fred Joslin