Author
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Topic: port velocity
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perk Gearhead Posts: 328 From: Staley,nc Registered: Sep 2000
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posted 05-03-2001 02:54 PM
Here's a good Question for all of you. Would small ports on the intake create more or less velocity to the heads ??? OR would it be better for the intake to have the same openings as the head ?? Now to me, in the 1st ?? it would seem with smaller intake ports you get a "stronger" flow of air. ON the 2nd ??,it would seem you get "more" air flow. Anyone want to explain this to an inquiring mind and tell which would be better on the 351c. thanks......perk
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jdsgallops Gearhead Posts: 285 From: Green Bay, WI Registered: Feb 2001
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posted 05-03-2001 03:40 PM
Although moneymaker is probably the best person to answer this question I will give it a shot. The ideal port shape is much like a funnel. At the throat you are looking for a cross section 85% of the valve diameter. You will look for a 1-2 degree angle from the plenum opening to that point. From what I understand the point at which the head and intake meet, you want the intake a little smaller than the head. This will help prevent reversion and not cause as much airflow disturbance. I hope this is the info you are looking for. Which is better, as you ask, depends on what you want the engine to do.
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perk Gearhead Posts: 328 From: Staley,nc Registered: Sep 2000
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posted 05-03-2001 05:42 PM
Good,here is why I'm wondering about all this.I have a holley street dominator with small ports and a Wiend X-celarator,which has ports the same as the heads.X-cel is on the Engine,along with a 292h cam and 4.11 gears.With this set up we are only 0.042 better than last year using the st.dominator,280h cam,and 350 gears. SO, Was wondering if maybe the holley might help or make it worse!!perk
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Moneymaker Administrator Posts: 12790 From: Lyons, IL, USA Registered: May 99
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posted 05-03-2001 06:07 PM
Street Dominator runners are way to small for anything but stoned stock cylinder heads and a 600 CFM carb. Have you ever advanced the cam yet? ------------------ Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member Fleet of FoMoCo products Moneymaker Bio US Class Nationals link
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perk Gearhead Posts: 328 From: Staley,nc Registered: Sep 2000
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posted 05-03-2001 09:22 PM
Yep,sure did Alex.Also got the new base plate on,lighter springs in dist.(Could not find the lighter weights).Added a 1in. carb spacer and went back to the 71/80 jets that came in it.Just came back from a test run and she's running great.I was just wondering about the velocity!! Thanks....I'll let you know the track results later.........perk
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