Help, what carb would you pick?
05-12-2005 | 06:09 PM
#14
Official OSO boat whore
Joined: Oct 2000
Posts: 6,157
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From: Mequon, WI
Re: Help, what carb would you pick?
Originally Posted by Whiteknuckle
Cord
The Holley Tech guy on their help line told me a rule of thumb is about 15% additional CFM required for Marine applications when using the formula that Rookie mentioned. From what I have seen on the dyno, that makes sense.
The Holley Tech guy on their help line told me a rule of thumb is about 15% additional CFM required for Marine applications when using the formula that Rookie mentioned. From what I have seen on the dyno, that makes sense.
Finally, got somebody to confirm my theory. Thanks!
05-13-2005 | 02:45 AM
#15
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Joined: Jul 2004
Posts: 1,229
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From: Stockholm, Sweden
Re: Help, what carb would you pick?
So that means that my new carb is to small 
I just bought a Edelbrock 750cfm for my (454*5100/3456)x1.15=770cfm...
An 800 would probably be more appropriate then
I just bought a Edelbrock 750cfm for my (454*5100/3456)x1.15=770cfm...
An 800 would probably be more appropriate then
05-13-2005 | 04:16 AM
#16
Off the Radar
Joined: May 2001
Posts: 1,097
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From: Cape Coral, FL or Colonial Beach, VA
Re: Help, what carb would you pick?
One point missed on the formula, you do not have a 100% efficient engine. You missed was deducting the efficiency factor. The average engine is less than 90%. Even top Nascar engine builders can not get 100%.
454 x 5300 / 3456 x 90%= 626. I always moved up some as did Cord. Any move up here is a guess. I would use a 750 Holley Double pump. 626 x 1.15=720.
454 x 5300 / 3456 x 90%= 626. I always moved up some as did Cord. Any move up here is a guess. I would use a 750 Holley Double pump. 626 x 1.15=720.
05-13-2005 | 06:00 AM
#17
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Joined: Jul 2004
Posts: 1,229
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From: Stockholm, Sweden
Re: Help, what carb would you pick?
Originally Posted by Linster
One point missed on the formula, you do not have a 100% efficient engine. You missed was deducting the efficiency factor. The average engine is less than 90%. Even top Nascar engine builders can not get 100%.
454 x 5300 / 3456 x 90%= 626. I always moved up some as did Cord. Any move up here is a guess. I would use a 750 Holley Double pump. 626 x 1.15=720.
454 x 5300 / 3456 x 90%= 626. I always moved up some as did Cord. Any move up here is a guess. I would use a 750 Holley Double pump. 626 x 1.15=720.
Thats right! Then I'm still ok with my 750...
05-13-2005 | 10:35 AM
#18
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Joined: Mar 2001
Posts: 2,558
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From: ohio
Re: Help, what carb would you pick?
Im spinning mine at 5400 with a 780 and a single plane and the vacuum is near zero. Ive always been led to believe that if you undersize the carb the wot vacuum reading will be higher.
