The pictured rockers are 1.6:1 ratio and available from Dove Manufacturing.  The Harland Sharp 1.6:1 rockers are similar except bronze bushed for the shafts and although the HS rockers have not been tested on the aluminum heads, they are expected to fit just like the Dove rockers as far as pushrod alignment goes.  For the aluminum heads, I’ve found that a different combination of left, right, and zero pushrod offset rockers are required versus the combination used on the iron heads.  I have a set of 1.6:1 Rocker Arm Specialist rockers here (on loan from Gary) and those look to be installable on the aluminum heads but some additional offset rockers will need to be ordered to make up a full pair of rocker arm assemblies for both heads.

Lorena, Texas (South of Waco)

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.  

  

    

Grizzly (Aussie Mainline)

Ted:

I noticed on the top picture with the old style rockers with jamb nuts it has different stands than stock.



Does the new head require these different rocker stands?

Does the new heads require a special length of push rod or will one of the three lengths of '55 and later y-block push rods Ford used fit.

marv

Now please tell me about those roller rockers?

Ratios availiable and where to obtain them.

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.

 

 

 

Lorena, Texas (South of Waco)

Now thats the kind of information I"m looking for.

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 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.

Frank/Rebop

Bristol, In ( by Elkhart) 

Oldmics,

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.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

Oldmics:

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

John - "The Hoosier Hurricane"

So the valves are the same size on the "G" heads as Mummerts?

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

Oldmics