I’ll take you up on your offer on that cast iron intake.  That particular manifold would represent the extreme end of what could be done with the iron intake manifolds.  I’m thinking that particular manifold is best tested on the mule engine with the angle milled heads just to take advantage of the increased compression ratio the engine will be seeing with those heads.  The following set of ported heads drops the compression ratio back to the 9.2-9.5:1 range which would negate some of the benefits of a highly ported intake where it would try to normally shine in the upper rpm ranges with the higher compression ratio.  But I’m in a position to test that intake on both sets of heads anyhow so the compression ratio can also be properly evaluated.

Lorena, Texas (South of Waco)

The ECZ-B intake can be modified to make good power but it takes a lot of work. We modified this intake before the B-T intake was available. Windows were cut in the upper runners to allow access to port turns. Floor was rounded to improve ramp to lower runners until the heat chamber was found. Holes were brazed and patches welded into ports. Made 425HP on 330 cu in Y.

Ted, I still have this intake if you're interested in a test.

http://ford-y-block.com 

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

Ted: That's interesting information. I'm sure most of us thought that a 3 carb setup,( in this case, 3- 97's), that the flow total would be approximately 465 cfm. In say percentage terms approximately how much flow does a Tri Power setup lose?

Paul

The Stromberg 97’s are generally rated at 155cfm when used individually.  Concensus has the Stromberg 81’s at 125cfm while the Stromberg 48’s are 170cfm.  The Strombergs with ‘LZ’ on them are rated at 160cfm.  The 3X2 intake manifold testing that was performed recently was with the Stromberg 97’s.  You'll have to remember that when the carbs are used in multiples, the cfm rating drops.

Lorena, Texas (South of Waco)

Currently working on a definitive test with the ported iron heads in regards to various single four intake manifold variations or mods.  I suspect that paticular intake modification (slotting) does standout more when the heads are ported than if used on stock heads.  From what I have observed, modifications to the intake manifold needs subsequent increases in head flow to realize any significant benefit.  Once the heads have been ported though, then the stock intake must be modified for more flow or an aftermarket intake used.

Lorena, Texas (South of Waco)

What is the approximate flow for a Stromberg 97?


Lawrenceville, GA

I've been told that the biggest improvement to the B is to open the Carb holes front to back to two eliptical holes. Then radius the area where the runner drops down to the rear two cylinders. Hard to reach that area until you open the plenum entry holes up. Has that been tested or is it conjecture?

Frank/Rebop

Bristol, In ( by Elkhart) 

Here are a pair of graphs from previous testing on the +060 312 dyno mule with stock G heads where a pair of ECZ-B intake manifolds were tested in a back to back test.  While one of the manifolds was stock, the other had its plenum opened up by removing the center out of the four holes that were present and the center divider itself was also lowered.  Both intakes used a 520cfm Holley and Reds Headers.  The modified intake was using a 2½” cloverleaf (semi-open) carb spacer that matched the opening at the intake flange while the stock intake used a Moroso 1” four hole spacer.  Based on the results, there was not much change in the horsepower values and only a subtle change in the torque.  As usual, this is just food for thought.

 

 

Lorena, Texas (South of Waco)

Haven’t tested slotted versus non-slotted on the B intakes.  Have bored out bores in the carb flange of the stock intakes though so they would accommodate larger bore carburetors but haven’t tested these against a dead stock intake manifolds either.

 

The stock intake is not overly responsive to the larger sized carbs and that’s simply due to the bottlenecking attributes (low flow numbers) of the factory intake.  The total engine package or combination must be considered when making changes and that means head and/or port work as well as any exhaust system mods must also be considered if contemplating intake manifold modifications.  The factory intake appears to be well matched to the stock heads but ends up being a bottleneck as the rest of the combination is being upgraded around the intake.

 

Here are a pair of graphs comparing the Mummert intake and a stock ECZ-B intake on a +030 312 (317 CID) iron headed engine combination that was dynoed recently.  The engine had a 228/238 cam ground on 110° lobe centers and installed 2° advanced.  The G heads being used were mildly ported and designed specifically for street use and with an automatic transmission.  A variety of carbs were also tested on this engine.

 

 

 

Lorena, Texas (South of Waco)

The Stromberg 97’s are unmodified and still jetted the same as when they were used in the 3X2 intake manifold testing that took place a short time ago.  The increase in vacuum in the higher rpm ranges points to the 97’s being on the small side for serious horsepower but being undersized does help to make the lowend torque numbers as good as they are.  With Barry Grant, Edelbrock, and Speedway all manufacturing brand new carbs for the older 3 bolt carb flange intakes, chances are good that overall performance can be improved without sacrificing lowend torque.

Lorena, Texas (South of Waco)