Before removing the Mummert aluminum heads from the dyno mule engine, a morning was spent in trying several other intake setups on the heads.  Final conclusion is that many of the early intake designs are going to be a bottleneck on the aluminum heads in the upper rpm ranges.  No surprise there as I see this also on ported iron heads.  For many of these intakes though, the low end torque values were still very strong which is a credit to the flow properties of the new aluminum heads.  The Mummert aluminum single four intake is still by far the best overall performer of all the intakes tested to this point and compliments the aluminum heads nicely.

The Cain 4V intake was tested at the tail end of this particular session and although the horsepower numbers with the Cane intake were stronger than the 3X2 and 2X4 setups with the aluminum heads in place, the torque curve still remains on the low side and lazy.   But compared to the last time the Cane intake was tested, the overall torque curve is much higher with this engine combination than as tested before.  The use of long tube headers in this recent test versus the short 'two tube' design used in the earlier test possibly accounts for most of the torque improvement.  Regardless, the open plenum and runnerless design of the Cain intake just isn’t conducive to making good peak torque numbers even when experimenting with a variety of carb spacers.  Here’s the graphs showing the Cain intake manifold’s best performance on the aluminum heads versus when it was used previously on a set of highly ported iron heads on a similarly sized engine.  Camming and headers were different on the two different engines being tested so it’s not an apples to apples test.

Lorena, Texas (South of Waco)

And here are a pair of graphs comparing the Cane and Mummert intake manifolds on the aluminum heads in a back to back test.  In this instance, the intakes were simply swapped with everything else remaining basically the same.  A variety of carbs and carb spacers were tried on the Cane manifold and what you see here is the best dyno pull with the Cane intake that resulted from that exercise as compared to the Mummert intake.  The carburetor ended up being the same for both intakes.

Lorena, Texas (South of Waco)

I've made tons of sketches of Y-Block intakes that will go past the limitations of our current street dual plane. I know some guys are going to want 500hp and trying to find that in anything that is available now is going to take a tremendous amount of work. There just isn't an easy way to make a true race intake for the Y-Block.

Still thinking about it.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

Could we have details???

Grizzly (Aussie Mainline)

John.  Here's some rambling thoughts on the subject.

Although I’ve only tested the Cain intake manifold on two different engines, the initial observation is that it does perform better with milder cams.  As the lobe centerline increases (overlap decreases), the lowend torque values do improve.  With the first homemade single plane intake that was on my Roadster, there was some reversion taking place at cylinders 1 & 2 although the intake was designed with full runners.  By making the runners longer and with a different degree of taper in the runners on the second fabricated intake manifold, lowend performance was significantly improved while the engine also saw an increase of thirty horsepower at its peak.  With no runners at all in the Cain intake, any overlap at the valves on adjacent firing cylinders really dampens lowend performance.  With this in mind, I may yet retry the Cain intake on an engine with a wide lobe centerline camshaft just to confirm this as this would just give another insight into intake manifold design while reaffirming my initial thoughts.

Lorena, Texas (South of Waco)

Using the same scoring methodology that’s been used in the past, here’s how each ranked from highest to lowest.

1885.4pts - Mummert intake with 1” 4 hole spacer and 750 Holley

1841.0pts - Ford ECG-D 2X4 intake with L1437 Teapot Holleys

1817.4pts - Edebrock 573 3X2 intake with Stromberg 97’s

1743.8pts - Ford ECZ-B iron 4V intake with 1” 4 hole spacer and 465 Holley

1728.3pts - Cain open plenum intake with 2” 4 hole spacer and 750 Holley

Here are a pair of graphs summarizing the overall performance of the various intakes that have been tested on the aluminum heads.  Interesting results to say the least especially in observing the torque curves.  You'll have to take into account that the 3X2 setup is essentially under-carburetted at this point as the manifold vacuum was increasing in the upper rpm ranges.

Lorena, Texas (South of Waco)

Porting,perhaps different carbs???

Do you think the 56 manifold with its more restrictive casting in the carb pads would be better or worse for horsepower?

Oldmics

Charlie, i came to same conclusion, the max figures seem to peak around 3600 rpm and that fits into everyday driveing range, most certainly any improvements on heads etc really keep the HP coming nearer top end range and should keep us further ahead of those other brands! Ted, big thanks for your informative graphs that make it easier to compare intake side of things.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia