I'd agree that the vic jr intake is probably not the best match for the stock heads on the ford crate. Certainly peak HP is only one piece of information to compare two engine, but it is a starting point. Here are some additional thoughts
1. Manifolds and RPM
I don't know who started this, but I see this relationship as more of an edelbrock marketing move. Heads are not sold for a specific RPM range and I think it is a little confusing when edelbrock sells manifolds this way. It perhaps an easy system for the public to grasp when really, manifolds "flow". They flow just like heads. I personally think a better approach to engine component selection is to match head flow data to manifold flow data. Too big of manifold on small heads and the engine is flat. Too small of manifold on big heads and you are making the engine breath through a swizzle stick.
2. Manifolds and Flow Data
Its hard to come by but can be found. Here are some sample numbers on edelbrock and Parker intakes....converting all to cfm 28 H2O and averaging the middle and end runners
Performer 200
Torquer 220
Vic Jr 260
Super Vic 320
Parker Funnel Web 305
the Performer RPM was not listed, I am going to take a wild guess and peg it at 210...right between Performer and Torquer
Data was collected from
http://www.jason.fletcher.net/tech/intakes/intakes.htm
http://www.fomoco.com.au/Funnelweb.htm
http://www.rfedd.bigstep.com/generic147.html
and so...if I were putting AFR 205s on an engine, and these peak flow
300 as low as .550 lift, well I sure as shootin would not want the Performer RPM intake since I am starving the heads for air. Likewise, if I was building an engine with AFR165 heads and a medium cam and these heads flow
248 at .550 lift, I would not pick a super vic or parker funnel web intake since that engine is going to be a dog at anything less than wide open throttle.
3. Dual Vs Single intake on a 393 w/ AFR 205s
Here is the chart with a Comp 276HR
http://www.cobralads.com/dyno2000/dual_single1.gif
Here is the area under the curve with the differences highlighted.
http://www.cobralads.com/dyno2000/dual_single5.gif
Green is where the single beats the dual and Yellow is dual beating the single. The single has more total area under the curve. The dual wins the 2000 - 3750 range and the single wins the 3750 - 6500 range. At this point I believe the intake choice is subjective to what a driver is personally looking for. Racing...I would want the green. Bragging rights...I would want the green. Daily driver...I'd probably choose the yellow.
Andy
Hybrid Mode
