About 5 years ago, Florida Phil asked if he should consider swapping his ECZ-B intake for John's aluminum intake manifold. In response to Phil's question Joe-JDC stated that the average flow for an ECZ-B intake manifold is 182-185 cfm; whereas, the Mummert intake manifold flows an average of 274 cfm. Has the ECZ-B intake manifold been flow-tested after opening the four holes to two ovals and blending the runners into the plenum? Results?

Phil, if you replaced your B intake with Mummert's without making any other changes (other than a larger carburetor), did you experience a "seat-of-the pants" increase in performance? If so, what was the effect below 3500 rpm?

It is hard to beat the Mummert aluminum intake manifold as cast with any other intake available.  The design is simply better in how the runners are shaped.  I have ported dozens of the Mummert, Blue Thunder, and iron ECZ-B intakes with and without the plenum opened up.  We(Ted/me) tested several different variety of intakes on the Engine Masters Challenge entry to find what worked best and made the most torque and horsepower within the rules provided for the Vintage Class.  The Mummert and BT were very near each other in horsepower and torque after I ported them both to the maximum.  The ECZ-B that I ported for this test went from 189cfm to 264 cfm.On the dyno, the 303Y as tested for EMC made ~437hp with the iron ECZ-B intake as shown here, and the Mummert made 454hp with every thing else the same.  This was with the Jones camshaft prior to the EMC.  The ported BT was within 3 or 4 hp of the Mummert IIRC.  Porting the iron intake was a major pain and I reworked it several times to try to match the Mummert and came up short every time.  Ultimately the Mummert that I used on my 375Y flowed 343cfm and made 593 hp with 930BG carb, and 613hp with the Mummert Single Plane intake.  Opening up the slot helped with porting and installing a heat spacer, and there is nothing shabby about 437hp with the iron intake on a street compression build.  Joe-JDC

JDC

Thanks, Joe, but no doubt that the B intake has had extensive port work compared to what Ted routinely does to customers' B intakes, like mine. 

I think the question, or at least the question i have, is what is drive characteristic and performance from switching from a b manifold to a mummert dual plane on a near stock engine

That's the million-dollar question, but I don't think it costs nearly that much. 

I received back in February one of the new single four barrel aluminum intakes made by Mercury 8 Restorations (M8R) in Australia.  I had Joe flow test manifold for me and in its out of the box condition with no modifications, that intake flows an average of 194 cfm.  That intake has the same size throttle bore holes as ECZ-B manifolds so upgrading to the larger bore size and slots will require the same work as being performed on the ECZ-B manifolds to permit the use of larger carburetors.

The plan is to run the M8R manifold on the 312 dyno mule in its stock form and compare its performance to both a stock ECZ-B manifold and an unmodified #548 Edelbrock single four barrel aluminum intake.  The #548 Edelbrock intake was designed specifically for the 1954 239 engines and that manifold flows an average of 148 cfm.  Here are pictures of both the M8R and Edelbrock 548 intake manifolds.
  

  

Lorena, Texas (South of Waco)

 Costs 545+ tax, shipping, and 2 dyno sessions, maybe 2 test and tunes for a more practical comparison as dyno doesn't always give full story. i don't have the knowledge, experience, or google skills to be able to find dyno comparisons to see low performance engine low rpm effects of increasing flow nearly 50%. You'd think it would have to drop due to lower velocity, but there's so many variables including weight, charge temperatures, plenum volume... Probably a waste of time wondering, researching, or even testing. if it wasn't for ybloke manifold and considering building my own manifold i would have bought it 3 years ago. 

The ECZ-B was opened up for the porting and flowing.

JDC