More power for the rat!
Race Director
Joined: Jan 2000
Posts: 13,018
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From: Corsicana, Tx
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Re: More power for the rat! (467-Ratman)
At least an 850, but if it was me I would use a Hp series Holley 950 annular. For every person that loves the Demons, I seem to run across ten that pitch them and go back to a Holley. Plus most absolutely hate calling BG for ANYTHING. Customer service is not a strong point for them.
In reality, I believe the Demon may be a great carb, but with all the tuning variables it allows it is easy for folks to get way too far out of the window so to speak. It happens on regular Holleys. Many times they can be fixed by going back to the original tune and slowly work from there.
Definitely go with the DP. There isn't a healthy big block alive that won't run better with a DP. No variables other than your foot. Also much easier to control during wheelspin... no rubber band effect.
Annular boosters work great on the street. They produce a stronger signal to get fuel moving quicker and atomized better at low speeds. Their only disadvantage is they tend to go rich at super high rpms. If that is an issue, you can tune with air bleeds. i doubt you will ever see an issue.
Your dual plane also is generally happier with a carb on the "large side". You are already helping low speed velocity with it, but since each cylinder only "sees" two barrels at WFO instead of 4 that a single plane does, it can benefit from a slightly larger CFM capacity.
About the only vacuum modulated carb I like is a Q-jet.. and even it has mechanical secondaries with an air door over them.
Jim
[Modified by 427Hotrod, 6:01 PM 6/24/2002]
In reality, I believe the Demon may be a great carb, but with all the tuning variables it allows it is easy for folks to get way too far out of the window so to speak. It happens on regular Holleys. Many times they can be fixed by going back to the original tune and slowly work from there.
Definitely go with the DP. There isn't a healthy big block alive that won't run better with a DP. No variables other than your foot. Also much easier to control during wheelspin... no rubber band effect.
Annular boosters work great on the street. They produce a stronger signal to get fuel moving quicker and atomized better at low speeds. Their only disadvantage is they tend to go rich at super high rpms. If that is an issue, you can tune with air bleeds. i doubt you will ever see an issue.
Your dual plane also is generally happier with a carb on the "large side". You are already helping low speed velocity with it, but since each cylinder only "sees" two barrels at WFO instead of 4 that a single plane does, it can benefit from a slightly larger CFM capacity.
About the only vacuum modulated carb I like is a Q-jet.. and even it has mechanical secondaries with an air door over them.
Jim
[Modified by 427Hotrod, 6:01 PM 6/24/2002]
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Joined: Aug 2001
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Re: More power for the rat! (467-Ratman)
467,
Annular boosters have little slots around the perimeter . They differ from downleg boosters. When you look down the venturis of the carb, you see a booster in each quadrant.
COntact Barry Grants tech and allow him to select the right carb for your requirements and based on your engine set up.
I had a 750 Edelbrock before, and the Speed Demon 850 knocks the socks off of the Edelbrock in performance. Like i said, it idles cold incredibly smooth around 900 rpms. You can get an accessorie chock for it if you want. But it wasnt needed on mine.
RR
Annular boosters have little slots around the perimeter . They differ from downleg boosters. When you look down the venturis of the carb, you see a booster in each quadrant.
COntact Barry Grants tech and allow him to select the right carb for your requirements and based on your engine set up.
I had a 750 Edelbrock before, and the Speed Demon 850 knocks the socks off of the Edelbrock in performance. Like i said, it idles cold incredibly smooth around 900 rpms. You can get an accessorie chock for it if you want. But it wasnt needed on mine.
RR
