Very interesting manifold flow comparisons. It should be noted that all
the test were run on 5.0 blocks with 600 CFM carb, and an aluminum
head. While "standardized" comparisons were made, the applicability to
your own engine set-up may be flawed.
Tiger "260" block, with stock heads, port dimensions, valves and cam
lift, may not conform to these results.
Comparisons were not made with the stock LAT 465 CFM Holley. The "260"
valve sizes and cam lift will influence comparisons. Additionally, the
actual port dimensions, vs. manifold dimensions, may strongly influence
results if there is a "step" up or down on a "match".
As a field test experiment, three "/identical/" stock 260 Tigers were
equipped with stock 2 BBL, cast iron manifold, and LAT-1 aluminum
manifolds with both Holley 465 CFM (standard) and 600 CFM carbs, and
stock 2.88:1 rear axle ratios, and 165/13 tires.
The results were interesting, subjective, and confirmed substantial
differences. Your own results may vary due to condition, tuning,
modifications.
1. For smoothness of running at idle, the 465 CFM and 600 CFM
versions were as smooth as the stock, although the 600 seemed to
"hunt" more.
2. At light throttle on dead-stop starts, they all seemed about
equal, except for some surging in the 600 CFM.
3. On "heavy-foot", but not rubber burning, take-offs to 35 MPH, the
465 was ahead, believed due to higher flow velocities.
4. On medium speed sudden acceleration the stock and 465 were about
as smooth, but the 465 was stumble free, and quicker than the 600
CFM. which "stumbled".
5. On freeway speeds, the 600 CFM seemed to have the edge (slightly)
over the 465 CFM.
Speeds over 70 MPH were not conducted. The 465 CFM was similar to the 2
BBL, but much quicker. The 600 CFM was good, after the sudden throttle
opening "stumble".
With "modified" engine breathing and/or port matching the results can
vary substantially.
Anyone else with similar comparisons, please chime in.
Steve
___
Steve Laifman
Editor - TigersUnited.com
rab65tiger@aol.com wrote:
> At Jason Fletcher's Carbureted 5.0 web site he has a list of? flow stats on a
>number of intakes for small block Ford, including performer, Tiger,F4B (note
>indicating Ford power Parts "Cobra", F4B and Shelby Cobra design all similar)
>and other intakes.
>
> http://www.jason.fletcher.net/tech/intakes/intakes.htm?
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