ATTN: Edelbrock #1407 Carburator Users

[The_Handier_Man1]

From: PhÃ¥rÃ¥oh  (Original Message)
Sent: 1/22/2006 11:36 PM

To all Group Members who have replaced your stock 440's carburetor with the 1407 Edelbrock carburetor.

I found that the stock orange step-up springs make the engine exhaust temperature run too high (my passenger side manifold was white from heat), and gas mileage takes a dump.  I recently made a 300 mile trip from Amarillo, TX to Lakewood, NM -- mostly flat with some gradually rising desert floors, average speed 55 mph on cruise control.  I went through my main tank like water -- 28 gallons = 138 miles, or 4.93 mpg.  That was with the orange springs.  The auxillary tank (18 gallons) made it 122 miles -- that was 6.77 mpg.

Guess what the difference was?  Right after I switched over to the auxillary tank, I stopped on the side of the road and changed the stock step-up springs.  I put in the blue ones from the Edelbrock #1464 Spring Assortment, and couldn't believe the difference -- 1.84 mpg!

You see, most of our rigs run from 4 to 7 inches of vacuum on this type of terrain.  The orange springs are set to stage rich at 5 inches -- which means that the least little incline causes the carburetor to deliver extra fuel when it doesn't need to.  The extra fuel raises the exhaust temperature, overheating the exhaust manifolds and lowering fuel mileage.  The blue springs are set to stage rich at 3 inches -- like on heavy acceleration, but not on gradual hills.

Your individual situation may vary, but it is possible that most of you could benefit from the spring change.  But I wanted to put the numbers out to you so you guys could decide for yourself.  The spring assortment only costs about $7.00, and you can change them in 5 minutes.

John



From: Liv42dayOK
Sent: 1/22/2005 11:52 PM

Good observation, John.   I know several members have gone to this carb, including me, and mine is running rich as well and the mpg is lower than expected (although I have to address the distributor/timing first) and will be evaluating the carb this spring.  My gas consumption is running only 6 mpg and should be better.  - Sob



From: Derrek
Sent: 1/23/2005 7:09 AM

I think that I posted this tuning link here before, but just in case some may have missed it..... http://www.telusplanet.net/public/gilesij/Volvord/edelbrock_1.htm


This is an excellent guide for tuning these Edelbrock carbs.



From: west coast redneck
Sent: 1/23/2005 12:45 PM

Eh John.I replaced my old Carter carb with a 750 cfm Elderbrock With electric choke last year.I went from 9 mpg to 13mpg.Runs & starts allot better too.Didn't change springs so don't know what type is in there now.Mine is a D21 brave with a 440-3.I know that our gallon up here is a little larger than yours but not that much different..I regularily check my mpg with both tanks and it's fairly consistant around 12 to 13.I don't understand why your getting such low mpg.I'm not fudging the numbers or anything.I'm fairly stock with a 727 tranny & original rearend.The only thing that I may have different is a 3 inch dual exaust.What kinda mpg is everyone else getting.?



From: Dave-Pam1
Sent: 1/23/2005 2:42 PM

I consistantly get around 8mpg with my new Edelbrock w/electric choke.  '73-440-4:56 rear end.  The biggest diference between the new carb and the old is that it starts now and the carb doesn't leak down when it sits...

Later,
David



From: HeavyHaulTrucker
Sent: 1/23/2005 4:13 PM

West Coast Redneck --

First, your carb came stock with the orange springs -- all of the #1407 750 cfm Edelbrocks come that way.
Second, how are you checking your mpg -- are you using your vehicle's odometer, or are you using a more accurate tracking device such as a GPS?  There is no possible way that you can be getting 13 miles to a gallon -- not physically possible with a 440 in a 10000 lb vehicle pulling a 19' boat.  Heck, it couldn't even approach that when it was new!  Even accounting for the larger Imperial Gallon that you guys use up there.  I think your odometer is way off.

==================================================

David --

Yours sounds about right, since you have the 4.56 rear end.  Mine has the 4.88 rear, so I am doing 2800 rpm at 55 mph.  Terrain has alot to do with it, too.

John