Dyno testing is now complete on the 3X2 intake manifolds.  The Edelbrock 573 was at the top of the heap with the Offenhauser being at the bottom.  There was a 29HP difference between the best and the worst which is a bunch.  The dyno test range for each test was 2500-5500 rpms.  Besides looking at both the peak and average horspower and torque values, the engine performance with each intake was also ‘scored’ to get a better feel for overall performance using a single value.  The score is calculated by adding both the average HP and torque together and dividing that into the cubic inch of the engine and then multiplying that value by 1000.  Testing concluded with the first intake being rerun at the tail end as a validation that the engine was holding steady and because there was still some time left at the end of the day, the new Mummert intake was installed with a 600+ vacuum secondary Holley on top of a 2” four hole spacer and also ran.

Here’s how the various 3X2 manifolds ranked in overall performance from the top to the bottom.

1. 1703.7 pts - Edelbrock ‘573’

2. 1674.7 pts - Edmunds ‘DM-425’ large port

3. 1672.4 pts - Edelbrock ‘553’

4. 1667.7 pts - Edmunds ‘DM-424D’ small port

5. 1661.2 pts - Weiand ‘FM436’ large port

6. 1646.9 pts - Edmunds ‘FORD 424’ small port

7. 1561.2 pts - Offenhauser w/no identifying numbers

The test engine is a +060 over 312 with 9.2:1cr, dead stock ‘G’ heads, and Harland Sharp 1.6:1 rockers.  The same Stromberg carbs were used on all the manifolds without any jetting changes once manifold testing commenced.  The camshaft is a Crower Monarch with 238° @ 0.050”, ground on 110° lobe centers, installed 2° advanced, and 0.434” lift at the valve after valve lash.  All testing was performed with four tube headers running through Magnaflow mufflers.  This series of 3X2 intake manifold testing is also part of the durability testing being performed on the prototype Harland Sharp rockers which so far appears to be holding up fine.

For those of you that live and breathe horsepower and torque numbers, here are the peak values for the 3X2 intake manifolds but are still being listed in their order of scoring.

1. 336.0 Tq / 279.3 HP - Edelbrock ‘573’

2. 336.1 Tq / 266.5 HP - Edmunds ‘DM-425’ large port

3. 334.1 Tq / 270.1 HP - Edelbrock ‘553’

4. 338.6 Tq / 260.1 HP - Edmunds ‘DM-424D’ small port

5. 332.1 Tq / 266.2 HP - Weiand ‘FM436’ large port

6. 330.4 Tq / 261.9 HP - Edmunds ‘FORD 424’ small port

7. 311.5 Tq / 250.8 HP - Offenhauser w/no identifying numbers

And here’s the order in which the intakes were run on the engine.

1. Edelbrock ‘573’

2. Offenhauser w/no identifying numbers

3. Edelbrock ‘553’

4. Weiand ‘FM436’ large port

5. Edmunds ‘FORD 424’ small port

6. Edmunds ‘DM-424D’ small port

7. Edmunds ‘DM-425’ large port

8. Edelbrock ‘573’ (reinstalled to validate earlier run)

9. Mummert single four intake with 600 Holley (291.9HP / 346.0Tq)

Intake manifold changes were down to 35 minutes each at the end.

Thanks for all the work and the clear presentation of the numbers...

Wasnt the mummert intake  a 4bbl?.

Thanks for all your hard work, the Y block nation commends your efforts!!!!

Which model Strombergs were used? Stock jets?

The compression ratio (9.2) on that dyno engine seems pretty low for the cam being used. It would seem that 10.0 or more might be optimal. What octane fuel was used?

Now I'm glad I traded my Offy 3-2 manifold for a pair of posted G heads!

Thanks!

91 octane pump gas is being used for all Y-Block testing at this point with the stock heads in place.  Total ignition timing is 38° BTDC using a MSD distributor.  Engine has 13” vacuum at 850 rpms for what its worth.  Performing a cranking compression check is on the list before changing the heads out for some heavily milled heads in the near future.  Engine sounds strong at idle even with 9.2:1cr.  118 pulls on the engine thus far and just now starting to pick up traces of some oil leakage from around the rear main seal area.

   I suspect all the aftermarket three-two intakes were developed before the '57's came out. Meaning that the only factory intakes available would have been the 2bbl's, or an A intake with a teapot. I'm not counting the dual quad intakes because those were really rare, I don't ever remember seeing one on the street.

Couple questions while you still have the intakes on hand, It is funny to note that the small port Edmunds DM-424D had the best torque numbers. What is the difference in the 2 Edmunds 424's? The one I sent you are calling the FORD 424. I did notice before I shipped it, it had been repaired in one runner which could have added a small restriction to that runner. I also noticed it had plenty of meat for hogging out, if you want to do an experiment by porting it out to a large port etc while you have the setup, have at it, I don't see myself needing it in the near future. You could then compare a ported 3x2 to a mummerts etc.

2nd, Do you have any low end torque numbers you could post? Most people don't get to hold their cars at the peak horse rpms very often, but they like the off the line tire fryer capabilities at the low end torque scale.

I’ll add that a problem with the Strombergs was noted before the testing even started in that the carbs would not open up fully even with the carbs off the manifold and in hand.  It  took some modifications to the carbs themselves to correct this problem but they worked much better than expected when it was all said and done.

3 Stromberg 97's     4.43 Sq inches  Venturi Dia 0.97"

The Holley 4 BBL     5.15 Sq inches

3 '56 Ford 2bbls       5.29 Sq inches  Venturi Dia 1.06"

3 Modified '56's       6.64 Sq inches  Venturi Dia 1.87" This is what the Edelbrock test used at the end.

Based on these numbers there seems to be plenty more in the 573 manifold and probably the others too. The vacuum under full load will be interesting.

It would also be interesting to see the results of a ported '57 B manifold.  Ted do you want one to try?

I’m at least 2½ months off before that particular test takes place so no there’s no real hurry right now.  The current plans are to test the various modified B intakes along with the Blue Thunder and new Mummert intakes on ported heads as I believe it’s a moot point to do that testing on the stock heads that are currently being used.

Ted, thanks for the info, i,m sure we can all say a big Thanks for the Unbelievable amount of R & D time you put in on our engines, its very enlightening the potential the engine does has, i believe all this testing and trying different intakes, combinations has never been done before and hence the y block was seen by the general populace as a lesser choice of engines, but the true believers can sit back and see it emerge through the clouds of doubt into the forefront of popularity! Thank you again. best regards bill.

Ditto to what "Cusso Bill " said .You are truely a living legend on Y-Blocks . I am sure you & JM ,along with a few others will go down in history as true believers .We can never repay you for your time & effort that you put into these magic  motors .I am certain you will be highly spoken of years to come .Once again ,a BIG thank you for your time .Words can not express how much we,on this site , appreciate it .You are truely worth more money .

Regards Lon

At pull #365, the short block was pulled down so a sleeve could be installed in cylinder #8 to take care of a lateral crack that was forming.  The engine was reassembled using the same rings and bearings as there was absolutely no wear on the bearings being evident.  Other than that, the engine has been rock solid.  This is the same basic short block combination that was put together in the Seventies and part of what I did on this end to prepare it for dyno testing was a rebalance with new rings and bearings.  I'll add that I installed bronze cam bearings to fix a twisted cam tunnel that was present when preparing this engine as a dyno mule.  The engine now has over 400 dyno pulls on it and still more testing with both heads and exhaust are in the works.

As carl said run it, just because it doesnt flow the best compared to the best doesnt mean its no good! And if you are happy and can feel an improvement, enjoy it! Get tired of comparisons and myths that dont compare to reality.

Here’s a graph displaying the torque curves for three of the 3X2  intakes that were tested on the 322” dyno mule.

Where the Edmunds intake has superior lowend performance for everyday driving and the Edelbrock has a very good high end capability with only a slight sacrifice in lowend power, the Offenhauser intake falls shorts on both ends of the scale.  Like Bill says, the Offy intake is still an improvement over a stock two barrel.

While I’ve never tried to equate dyno pulls to a highway mileage value, I have for my own record keeping purposes considered each dyno pull the equivalent of a ¼ mile dragstrip pass.  In answer to Ivan’s question, then the dyno mule would have well over 100 miles of full throttle operation.  Relating that to a street mile value would be difficult and would not be the same for all engines depending upon compression ratios and other factors within the engine.  But for the dyno mule in a ’57 Ford being used by a teenager, let’s call the 400 plus dyno pulls roughly 4500 miles and total life expectancy of the engine in the neighborhood of 12-14K miles.  While the engine is holding up fine, I’m reasonably sure that a large number of trannies have been in and out of that teenager driven car by this point.  I’m obviously digressing here.

In the case of the 312 dyno mule, the engine bottomend was disassembled and examined closely at pull number 365 when a cylinder wall needed servicing due to a crack in it.  The engine bearings still looked extremely good at that point.  Good enough in fact that they were reused and the engine is still running strong today at well over 400 dyno pulls.

One thing I have found regarding engine life is the general tuneup.  If the engine is always kept in good tune, then engine life is greatly extended.  Any issues with fuel mixtures or ignition timing speeds up any wear issues that may be cropping up.  Fuel wash ends up damaging the cylinder walls while ignition timing variances are destructive to both the valves and the engine bearings.  Fuel injection and electronic ignition are both big players in keeping an engine in top tune and keeping wear factors to a minimum.

The dyno mule is currently being tested with a Teapot intake manfold and that’s being used to sort out some Lincoln Teapot carbs.  With another cylinder head change in the works, the engine will be used for an extensive dual quad intake test this upcoming winter.