Ted,

Thanks for all of the great info. I see your on your +.060 312 mule you said that the pistons were stock .025 in the hole.  Were you using the Best Gaskets?  I have a 312 that looks like it will be .040 over. and stock G heads.  If  I keep it .025 in the hole and Best Gaskets do you think I could squeak by with a static compression of around 9.0:1?  Thank you.

I'm constantly amazed by the work that everyone puts into this website and their willingness to share. Thanks Ted. This was more than an amazing write up.

Heber City, UT (15 mins outside of Park City- basically it's in the mountains)

55 Effie

I was really disapointed in the 471's performance, until I realized I was comparing them to  other ported heads.with more compression. Looks like the 113's were fairly good heads. Thank you Ted, unbelievable amount of work and time expended for free.

                                              Frank

Frank/Rebop

Bristol, In ( by Elkhart) 

The dyno engine in this test is a +060 over 312 with the cast pistons still 0.025” in the hole.  Basically a stock rebuild other than the amount of overbore and a Crower camshaft.  More details on the rest of this engine are available at the start of this thread.

 

As a general rule, porting the stock heads will sacrifice some of the lowend torque values for upper rpm performance.  That has to do with the air velocity at the lower rpms slowing as the intake ports are either made larger or the port walls themselves made smoother.  The intake manifold becomes a serious player once head porting is done.  If the intake manifold does not flow at least as much air as the modified heads, then the intake itself will hold back the potential of the head porting.  And then the actual valve job is a player.  Subtle changes in seat angles can help or kill cylinder head flow which was part of the problem with the larger valves in the COAE heads.

 

If an engine is not going to be romped on where it sees 5500 rpms or more, then it starts to become a moot point to change intakes, carbs, cams, head porting or any of those other modifications that helps that seat of the pants performance feel.  Fuel economy is another subject though.  For those Y engines that rarely see over 3500 rpms, then the stock 1957 292 or 312 engines give a good basic blueprint for the best combination between efficiency and performance.  For those of us that want more performance, then head work is at the top of the list.

Lorena, Texas (South of Waco)

The heads that scored higher produced higher average hp and tq. Peak is for bragging rights. Averages, getting the power up and keeping it there, are what really counts. An engine with less peak power can be the more powerful engine.


Lawrenceville, GA

Thanks for posting those numbers.

The numbers i find most interesting are

g-stock heads out perform g-gh heads even though the stock heads are down by 12 horsepower.

g-mt heads out perform g-yellow brick heads with the g-mt heads being down 24 horsepower and 13 torque.

113-lp and g-mt score about the same with the g-mt heads being down almost 30 horsepower.

This is a good test but for me i have more questions then answers.  Also a lot of whys, how comes and what ifs.  I wonder on a stock 292 with a stock cam and intake how these heads would perform.  Why did the coae heads with the larger valves not do well?

Ted this engine is a 312 right.  You said to score the engine divide by the cubic inch (322).  Is this engine a 312 with a 60 overbore or is 322 a misprint.

Thanks again for the numbers and all the hard work-Greg

In lieu of a bunch of graphs that get busy in a hurry, here’s a revised chart using a scoring format to gauge the overall performance.  While I've calculated the scores in the normal 2500-5500 rpm range, I've also included the scores for the 2500-3500 rpm range as this gives a better idea of the lowend torque values of the various heads.  This information was already compiled and comes from the in-depth article that will be in a future issue of the Y-Block Magazine.  The scores are calculated by adding together the average torque and horsepower numbers for the given rpm ranges, multiplying by 1000, and dividing by the cubic inch (322).  The table format in this instance with the scores gives a better overview than a crowded and busy graph.

 

Cylinder Head	Peak HP	Peak Torque	Comp Ratio	Ported	Score 2500-3500 rpm	Score 2500-5500 rpm
Mummert Aluminum	377	368	9.8:1	Yes	1781	1892
Mummert Aluminum	354	356	9.8:1	No	1633	1852
113 – LP	333	350	9.2:1	Yes	1592	1829
G – Yellow Brick heads	328	350	9.4:1	Yes	1586	1818
G – MW	324	349	10.6:1	Yes	1621	1841
G – MT	304	337	9.6:1	Yes	1591	1825
G - GH	302	337	9.2:1	Yes	1557	1749
G - stock	290	344	9.2:1	No	1633	1755
471	296	332	8.3:1	Yes	1517	1720
ECZ-C – stock – JF	288	336	9.0:1	No	1560	1733
ECZ-C – stock – CL	280	335	8.6:1	No	1556	1709
ECZ-C – stock – JM	273	330	8.1:1	No	1525	1676
ECZ-C       after milling	295	339	9.0:1	Yes	1548	1754
ECZ-C       before milling	290	334	8.4:1	Yes	1535	1726
C1TE-D    after milling	297	337	9.0:1	Yes	1571	1754
C1TE-D    before milling	295	335	8.4:1	Yes	1554	1738
COAE-A - stock	283	332	8.7:1	No	1566	1709
COAE-A w/larger valves	273	328	8.9:1	No	1525	1668

 

I’ll add that the ported aluminum heads really shine on those engines that are built to accommodate them.  My roadster engine with the aluminum heads is now peaking at 520 ft/lbs of torque and that was enough to rip the planetaries to shreds a week ago at the Houston NMRA/NMCA race.  Lots of runs on that particular transmission so it wasn’t a total surprise when that occurred.  It’s just the first time I’ve done that kind of carnage with a Y-Block in front of the transmission.

Lorena, Texas (South of Waco)

Hi

Im new but have been on the outside looking in for a long time.  I was wondering if the power curve data is available for this head test.  Im curious to see what rpm these max horse power numbers occur (also the torque).  In my opinion just the max numbers are a little misleading and don't tell the whole story. 

Thanks

Ted, many thanks for all this info. I am amazed that the 1.64" intake C0AE heads run a well as they do. It looks like C0AE heads with 1.78 or 1.84" intakes and a little blending would make a good street head.

The C1AE heads are much harder to find but do have some subtle changes. Hard to say if they are any better.

A rare head that intrigues me is the ECZ-C-ED. They were used in 56, on pick-ups as far as I can tell, have 1.78" valves and -113 combustion chambers with 1957 style ports. Looks like a good street head. Very HTF.

http://ford-y-block.com 

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

Yes for the stock COAE heads.  No for the C1TE heads.

Lorena, Texas (South of Waco)