Can this thread compare the engineering differences between Mummerts heads and an original stock set of non posted "G" heads.

I have gleamed some of the differences by reading the existing posts in all of the topics but thought a dedicated post for comparing might be helpfull for quick references.

Also any porting suggestions ? Isnt that terrible

All that work and were just waiting to grind em up

Oldmics

I'm on the East coast now up in Maine. I could be wrong, but I don't think John's new aluminum heads have the bigger intake valves like the "G" heads.

Rono

Rono.

What is different about the new heads that makes them superior?

Oldmics

Intakes are the same, exhausts are .030 bigger than G heads.  What makes them superior?  John Mummert's expertise.

I think you will find there has been port flow improvements & combustion chamber efficiency over the cast heads and for me, the dyno figures indicate somethings different.

       The ports are vastly superior as cast, and they get better with a grinder. If you know how. The combustion chamber design improves the valve shrouding issue, and requires CONSIDERABLY less timing. Means it works better. the heads are less than half the weight of the factory heads and the engine runs cooler, although the water temp will likely be higher!! work on that for a while! Ted picked up 50+ hp with a set.

Is there a diagram of the original head ports and then an overlay of Johns improvements to the ports for comparison.

I"m curious what he did to the ports? Moved them in the new castings-changed the pattern?

Oldmics

The intake valve has been moved closer to where the exhaust valve was or away from the edge of the cylinder wall.  To help this along, the exhaust valve was placed closer to its adjoining cylinder wall.  Both the intake and exhaust valves have also been relocated higher in the bore and closer to the intake manifold.  All this makes for better flow numbers before port improvements come into the picture.  The ports themselves have also been reconfigured internally which just adds to the improvement in flow seen from relocating the valves.

The oil drainage in the valve cover area has been greatly improved on the aluminum heads.  Oil drainage is no longer relying solely on the two oil drain holes at each end of the head as the new head design has oil drainage taking place at some of the pushrod holes.

Add to the list of improvements the use of 14mm sparkplugs and redesigned combustion chambers.  The 14mm spark plugs do sit more inboard than the 18mm plugs on the stock heads which at the bare minimum gives additional spark plug wire room around the headers.  The combustion chamber design likes less total timing which makes the combustion more efficient.  Brake specific fuel numbers are lower which points to better fuel economy if the driver can keep a light foot on the throttle.

Ratios availiable and where to obtain them.

Oldmics

On the contrary removing the "as cast" finish is know to improve flow. A linished finish is desirable not smooth or polished finish. I'm interested where in the RPM range this linished finish will provide an increase. It could be that the next step could turn them into racing heads and better in the WOT, high RPM applications.

As these head are released I'm sure that there will be tuning tips and HP will increase accordingly. As people try different things in there own application. Porting is the obvious next step and of course there is different levels of porting. I think John has put more material in the port walls to accommodate racers and additional porting.

I'm guessing that when John Sits down and ports the heads for the racer trial the flow bench will reveal some secrets.  

I assume (you know what happens when you assume ) Mummert is selling the longer push rods?

Oldmics

Why not keep things in perspective! just ask john, i think you will find that after developing these heads, he, john has the accompanying parts to make it all work!!:

Valves were moved closer to the intake manifold. Rocker shafts also needed to be moved to retain the same distance from the valve stem to the rocker shaft so existing rockers could be used.

Intake valves were moved toward the exhaust valves. Exhaust valves were moved away from the intake valves. Current valve spacing is 1.815". This limits total valve diameter of intake and exhaust valve to 3.52".

Spark plug has been moved closer to the exhaust valve while Ford put the spark plug on the exact centerline of the cylinder. Spark plugs are now 14mm instead of 18mm.

As you might guess the ports are not as large as they could be. We needed to make a streetable head for engines as small as 298 cu in ( .030 over 292).

Intake valves are 1.94" as sold. We have already done some porting and testing with 1.98" intake for Ted's EMC engine. We have tested a lower intake port @ 274CFM and 255CFM with a ported intake installed. This pencils out to 500HP+

The angled portion of the exhaust ports (all 4 have them) is one place where you can hit water when porting.  The water jacket in that area is there because of the spark plug location.  Compare the plug locations of John's and Ford's heads.  John doesn't need that angled water jacket casting.  By the way, '54 heads had squared ports, they used 14mm plugs instead of 18mm.

Oldmics

Here’s what John said awhile back regarding flow numbers on ported iron heads