Carburetor Recommendation
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Senior User
Joined: Jan 2002
Posts: 438
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From: Centreville USA
Carburetor Recommendation
I asked the Demon Carb tech people for a carburetor recommendation for my engine/car. The specs are as follows:
The engine is a 390 ci FE installed in a 1964 Ford Galaxie 500 convertible. It is rebuilt basically stock with the following exceptions:
Intake manifold - Aluminum Offenhauser 360 degree single-plane manifold
Cam - Hydraulic, .486/.512 (intake/exhaust lift), 204/214 (intake/exhaust .050 duration)
True roller timing chain
Stock exhaust manifolds (plan on upgrading to headers in the future) feeding a dual 2.5" exhaust (no H-pipe) with Flowmaster mufflers
3-speed manual transmission with overdrive
The car is not raced (except maybe the occasional stoplight) and is mainly used for weekend trips and cruising.
They recommended the 750 cfm Speed Demon. I think that may be too much carb for a street driven engine and that a 650 cfm Speed Demon would be more appropriate. The engine has just a slight lope with the cam I have installed. What do you all recommend? I am pretty much settled on a Demon (don't like the looks of the Edelbrock, Holley is OK). Thanks.
The engine is a 390 ci FE installed in a 1964 Ford Galaxie 500 convertible. It is rebuilt basically stock with the following exceptions:
Intake manifold - Aluminum Offenhauser 360 degree single-plane manifold
Cam - Hydraulic, .486/.512 (intake/exhaust lift), 204/214 (intake/exhaust .050 duration)
True roller timing chain
Stock exhaust manifolds (plan on upgrading to headers in the future) feeding a dual 2.5" exhaust (no H-pipe) with Flowmaster mufflers
3-speed manual transmission with overdrive
The car is not raced (except maybe the occasional stoplight) and is mainly used for weekend trips and cruising.
They recommended the 750 cfm Speed Demon. I think that may be too much carb for a street driven engine and that a 650 cfm Speed Demon would be more appropriate. The engine has just a slight lope with the cam I have installed. What do you all recommend? I am pretty much settled on a Demon (don't like the looks of the Edelbrock, Holley is OK). Thanks.
Posting Guru
Joined: Feb 2004
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From: Jackassville
first of all it has proven that edels have more power, relaibleity, and better air/fuel miture than the holleys. but if you inist on spending the money than i would definlty go with the 650fm carb over the 750 is to much.
Post Fiend
Joined: Jan 2003
Posts: 8,600
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From: Iowa
Originally Posted by FERacing66
first of all it has proven that edels have more power, relaibleity, and better air/fuel miture than the holleys. but if you inist on spending the money than i would definlty go with the 650fm carb over the 750 is to much.
I'd think a simple Holley 650cfm vacuum secondary would work great. No need to spend the $$$ on a demon.
Lead Driver
Joined: Apr 2001
Posts: 6,175
Likes: 21
From: Texas
Even looking at the Barry Grant site, that seems like a big carb for your application. That's the same carb they reccomended for my 446 with a 228at50 duration cam.
I think the 575 or 650 is adequate. You might even be able to use one of their mor affordable Jr. carbs.
the BG carbs tend to flow better than labeled.
here is a Jr. part number that fits the description to your app.
Part # 6402020 VFE
725 Road Demon Jr with Ford kickdown linkage and optional electric choke
Stock or Mild performance applications with 383-409 CID V8 engines
about $300at Summit.
I think the 575 or 650 is adequate. You might even be able to use one of their mor affordable Jr. carbs.
the BG carbs tend to flow better than labeled.
here is a Jr. part number that fits the description to your app.
Part # 6402020 VFE
725 Road Demon Jr with Ford kickdown linkage and optional electric choke
Stock or Mild performance applications with 383-409 CID V8 engines
about $300at Summit.
Lead Driver
Joined: Apr 2001
Posts: 6,175
Likes: 21
From: Texas
That's a Road Demon Jr. They cost a good bit less than the Speed Demons etc. But for a cam that mild, I think the Jr. is adequate.
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Post Fiend
Joined: Sep 2000
Posts: 8,238
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From: Oregon
Originally Posted by FERacing66
first of all it has proven that edels have more power, relaibleity, and better air/fuel miture than the holleys. .
Greg is indeed correct that the Demons flow at higher capacities than the other brands at the same advertised volume, due to they way they are measured. The long and the short of it is that you would indeed be fine with a 650. I'm not a big fan of the jr.s, but at this point in your combo it would be a good match for your current setup. If you ever plan on expanding on your build I'd go for the 650 sd to give you room to grow.
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Senior User
Joined: Jan 2002
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From: Centreville USA
I don't recall. I would have to pull out the paperwork. The engine came from S&S Auto Engine Remanufacturing (http://www.rebuilt-auto-engines.com/ford-engines.html) out of Spokane, Washington. It is whatever they install as the next step up over a stock cam.
Posting Guru
Joined: Feb 2004
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From: Jackassville
acctually most people with daily drivers and raers use edelbrocks. holley is good but EVERYONE ive talked to incuding people on this forum have said after using both brands the edels are way better.
Postmaster
Joined: Jul 2003
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From: iowa
Originally Posted by FERacing66
acctually most people with daily drivers and raers use edelbrocks. holley is good but EVERYONE ive talked to incuding people on this forum have said after using both brands the edels are way better.
Senior User
Joined: May 2004
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i have a demon
i have a 74 f-100 with a 390, mine is built up slighty but i was running a 600 holley then i put on a 750 holley, both were vac sec. the 750 didn't seem to do anymore then the 600. soooo, i went to my local speedshop and they recommended a demon 750 mech sec. BOY what a difference !!!!! i never thought a carb could do such things !!! don't be worried about tuning the demon either, same as a holley and most parts are the same. i love laughing a rice rockets now !!! they never knew what hit em !!!