All Big Six ProMAXX CNC ported big valve heads are now available.

Relates to all big sixes

pmuller9

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ProMAXX Performance Products now has CNC ported big valve heads available for the Ford big six.

The heads are based on NEW thicker EFI style castings.

The combustion chambers are unshrouded to 73 cc using CNC machining.
Because of the thicker casting both the intake and exhaust have hard valve seats installed rather than just the exhaust.
The valves are stainless steel 4.910" long 1.94" intake and 1.60" exhaust.
The head comes assembled with valves springs suitable for most hydraulic cams.
If you need a different spring for a different application it can be substituted for the difference in spring cost.
The rocker towers are standard height for stock pedestal mount rocker arms or the Scorpion roller rocker arms.
If you want the towers machined, drilled and tapped for 7/16" rocker studs it can be done as an option.

Use a 9/16-18 set screw to plug the smog pump air holes that lead into the exhaust port.

The intake flows
218 cfm @ .500"
225 cfm @ .600"


Fully assembled price is $1398

This head is not listed on their website

Contact Jason



ford 6 clinder 3.jpg

ford 6 clinder 2  .jpg

ford 6 clinder 1 .jpg
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ford.jpg
 
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pmuller9

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The the valve guide boss has been contoured with the bridge left behind the guide for "steering"
The area on both sides of the guide boss has been opened up and deepened for flow.

The intake flowed 218 cfm at .500" lift and 225 cfm at .600" lift but continued to flow with a slight increase as the valve was open further.
The ported Ford stock castings flow stalls after .600" and may even decrease after that point.
 
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pmuller9

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Will you and Gramps still be offering your own ported cylinder heads?
No
We were looking for someone to do a CNC ported head and ProMAXX is filling that need.
Gramps is concentrating on the aluminum crossflow head.
 
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pmuller9

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That was the Sr head, right?
Are you still offering the Jr head which was going to be hand ported?
Yes The ProMAXX head is the SR head.
The 300 six needs all the flow an iron head can produce even for low rpm stump pulling applications.
We decided that the intermediate JR head was not needed.
 

bubba22349

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Are the intakes and exhaust port ported too? It appears like it's a major upgrade improvement in a bolt on package! Combustion Chambers and valve pockets are very nicely done. A head with about everything needed for excellent Carb or EFI street performance.
 

pmuller9

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Are the intakes and exhaust port ported too? It appears like it's a major upgrade improvement in a bolt on package! Combustion Chambers and valve pockets are very nicely done. A head with about everything needed for excellent Carb or EFI street performance.
Yes, if you look at the top picture you can see the smooth port walls.
 

bubba22349

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Thank you pmuller9, couldn't see it before this time of day get a bit of glare on my screen.
 

Soldmy66

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Has anyone done a stock head vs ProMAXX CNC ported big valve head dyno comparison, with the head being the only variable?
 

pmuller9

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Has anyone done a stock head vs ProMAXX CNC ported big valve head dyno comparison, with the head being the only variable?
Not Yet.
The comparison should be made with a 10:1 compression engine with a large street/strip hydraulic cam, headers and an intake with at least 650 CFM carb or TBI.

You could be the first.
 

Soldmy66

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Not Yet.
The comparison should be made with a 10:1 compression engine with a large street/strip hydraulic cam, headers and an intake with at least 650 CFM carb or TBI.

You could be the first.
Well, it isn't that I wouldn't be interested ... but I don't have a 300 in either my 57 Chevy 210 Wagon or my Infinity G35. I sold my 200 long ago, but I am still addicted to this forum.
 

pmuller9

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This head is about the best that anyone can do as a modified iron head.
As far As I know, no one else in the country has a CNC set-up for these heads.

You may squeeze out a few more cfm from these heads with undercut valve stems and a little more attention to the valve head itself but there's not much more to be gained over the out of the box ProMAXX CNC machined head.

There are 5 in stock ready to ship at the moment.
 
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InlineDave87

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Once my house sells im grabbing me one of them heads... they are gonna be perfect for what im gonna do with my truck later šŸ˜ˆ
 

pmuller9

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Where has the head thickness been increased?
ProMAXX looked at all the areas on the head that had problems one of them being cracks in the combustion chamber area.
So when they had the castings made more material was added in those areas.

There is more material around the combustion chamber area.
The thicker chamber area allows valve seat inserts to be installed for the intake valve.
If you try to install intake seats in the original Ford heads you can run into the water jacket.
 
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