Carb Question!!!!

89Saleen243

New Member
Nov 28, 2002
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What is the best carb to run on a street 347 in a 65 fastback. Here is a snapshot of the engine make up: Ported Gt40 X heads, X303 Camshaft, Edelbrock Victor Jr intake. How much carb do I need to feed this engine???
 
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alot of guys at my shop tell me that edelbrock carb's seem to make the engine rev up slower and will be a little slugish.They all say Holleys the best.Ive never gotten the chance to test them against each other.At Universal Technical Institute they only use Demon carbs in there Hot Rod U class.
 
Well, so far I've had a 500 carter, a 625 carter, a 750 edelbrock, 600 holley, 700 holley and a 850 holley on my 347.

The 850 ran the best on top, but always fouled out plugs.... The 700 Holley has been the best all-around carb with killer top end power and without killing plugs (and gas milage) As of right now, the 347 is using the 750 edelbrock. Decent performance, probably less tempermental but losses hands down to the holleys.
 
89Saleen243 said:
What is the best carb to run on a street 347 in a 65 fastback. Here is a snapshot of the engine make up: Ported Gt40 X heads, X303 Camshaft, Edelbrock Victor Jr intake. How much carb do I need to feed this engine???

You're better off with under-carburetion than over-carburetion. You pick the brand, but 650 cfm is the mathematical choice for a sbf. I got the Holley Street Avenger 670 and really like it except for those useless clear bowl lenses...since replaced. They also come Ford linkage ready.
 
i'd say it depends a lot on tanny choice as well. if you are running a standard go with mechanical secondary. if you are using an automatic then i'd go with a vacuum secondary. personally i like demon carbs for tunability and max power and edelbrock/carter carbs for streetability and dependability. but the cfm ranges everyone has suggested are pretty much right on, but demon seems to rate their carbs a little lower since they are way more efficient than a comparable holley, so a 750 holley would equate to a 650 demon and a 650 holley would equate to about a 625 demon which is what i am running right now
 
bnickel said:
i'd say it depends a lot on tanny choice as well. if you are running a standard go with mechanical secondary. if you are using an automatic then i'd go with a vacuum secondary. personally i like demon carbs for tunability and max power and edelbrock/carter carbs for streetability and dependability. but the cfm ranges everyone has suggested are pretty much right on, but demon seems to rate their carbs a little lower since they are way more efficient than a comparable holley, so a 750 holley would equate to a 650 demon and a 650 holley would equate to about a 625 demon which is what i am running right now


ok that didn't make as much since after i read as what i meant to say, let me try again. you will make the same amount of power with a 650 demon as you would a 750 holley and the same with a 625 demon as with a 650 holley, because the demon is so much more efficient than the holley, ok that sounds better