Help with carb selection
Thread Starter
Safety Car
Joined: Jun 2005
Posts: 3,841
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From: Inver Grove Minnesota
Help with carb selection
I have a 350 with Aluminum heads, 2.02/1.68 about 9.5 to 1 compression and a 274 advertised duration cam. Currently I have a 750 dual feed on there but this just seems like way to much carb to me. Would I be better off with a 650 or something along those lines?
Here is the results of desktop dyno:
Here is the results of desktop dyno:
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Dual plane can use a larger than single plane
VS can be bigger than a double pumper
I ran a vs 650, vs 750, and demon 820 on a 355 single plane
I wish that I would have not sold the 650
VS can be bigger than a double pumper
I ran a vs 650, vs 750, and demon 820 on a 355 single plane
I wish that I would have not sold the 650
Advanced
Joined: Oct 2004
Posts: 62
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From: Bowling Green KY
The 750 vacuum is a pretty good choice. The good thing about the vacuum secondaries is that they won't start to open until the engine needs the extra cfm. Velocity flowing through the primaries is what opens the secondaries. You can fine tune the carb by going to a lighter or heavier secondary spring, and this will increase or decrease the speed which the secondaries start to open.
However, you would most likely see better throttle response with a smaller carb, and with a light secondary spring you most likely wouldn't notice much performance difference. I would stay away from a double pump carb on this engine.
As far as jet size, all you can really do is look at the plugs and go from there. General rule is that it takes about two jet sizes to make a noticable difference.
However, you would most likely see better throttle response with a smaller carb, and with a light secondary spring you most likely wouldn't notice much performance difference. I would stay away from a double pump carb on this engine.
As far as jet size, all you can really do is look at the plugs and go from there. General rule is that it takes about two jet sizes to make a noticable difference.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
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How much are you willing to spend for a carb ?? with your 410s, wide ratio super T-10 believe you would like a double pumper carb better. 650CFM would be enough air for a 5600 rpm
350 even with improved heads, exhaust.
350 even with improved heads, exhaust.
Last edited by Little Mouse; Aug 11, 2008 at 02:31 PM.
