Cylinder heads valves and rockers

81slantnosewp

Well-known member
Head, Valve, and Rocker:
current development/R&D
ORIGINAL ALUMINUM HEAD (in our announcement section)
JR, SR, X-FLO (Bruce aka Gramps)
RACE ONLY ALUMINUM HEAD(NO WATER PASSAGES) if you have over $10k I'm sure he would make another
(best quality link assistance)

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



View attachment 5396

View attachment 5397
The big valve, CNC ported head is not on their website.
This thread is serving as the advertisement for the performance Promaxx head for the Ford 300 six.
You need to call Promaxx and order through Jason.

can be contacted by email at jason@promaxxperformance.com


NO LONGER AVAILABLE:
2 types of a limited experimental run of cross-flow heads by ford in research and development (never available to consumers or placed in the production of any vehicle or application)


USED IN.
The 240 cu in (3.9 L) six for 1965–1972 full sized cars (continued to 74 in fleet models) and 65–74 trucks or vans produced 150 hp (112 kW) (gross). In stationary service (generators and pumps) fueled by LPG or natural gas, this is known as the CSG-639. The 240 had a bore of 4" and a stroke of 3.18".

The 300 cu in (4.9 L) six was added for the F-series in 1965. It is essentially a 240 cu in (3.9 L) with a longer stroke. The two engines are nearly identical used from1965-1996 (1997 in F250/F350 only), but in 1987 the 300 was converted to fuel injection, which used a different head.

240 heads have a 68cc kidney shaped combustion chamber.

300 heads up to 1986 have a 76cc semi oval combustion chamber.

1987 and later heads have a 68cc kidney or heart shaped combustion chamber. These are the EFI heads

The EFI heads have an extra three bolt holes to support the exhaust manifolds.
prior to 87
87 and later

they also have an extra mounting location for serpentine bracket on opposite side
smog/thermactor holes some 300 heads have them others do not



Heads up to 1984 have stud mount rocker arms with slot shaped pushrod holes in the head to act as pushrod guides.
Up to 1977 (unconfirmed) the 3/8" rocker studs used a 3/8 x 24 self locking adjusting nut.
The 1978 to 1984 heads use a shouldered 3/8 positive stop rocker stud with a 5/16" x 24 nut with no adjustment. The nut is torqued to the stud shoulder.(image assistance appreciated)

1985 and 1986 carburetor heads and 1987 and later EFI heads have pedestal mount rocker arms with round holes in the head for the pushrods.
1984 and earlier heads use a 4.810” long valve while the 1985 and later carb and EFI heads use a shorter 4.750” valve.
All have 11/32” valve stem diameter, 1.780" intake diameter and 1.559" exhaust diameter
SI valves is the main source for 240/300 valves that are the 4.750" and the 4.810" long stock lengths.

If the head is converted to screw-in rocker studs then the SBC 4.910” long valve can be used for oversize valve installation as well as the SI 4.810" long Ford 300 1.94"/1.60" valves.
The 1985 and later heads will need pushrod guide plates when converting from pedestal to stud mount rocker arms.
oval pushrod guide holes
large circle pushrod holes
chevy valves
chevy rockers

Additional Note: The 1985 and later heads with the short 4.750" valves will have valve retainer to valve guide clearance issues with valve lifts near .500".
Will need to use longer valves either the 4.810" or longer depending on the valve lift.

FTF and others have noted that the exhaust valve rotators ought to be removed in high rpm applications

Note on roller lifters: some machining may be required to install lifters with link bars


EngineQuest makes an aftermarket EFI style head both bare and assembled.
allied motor parts keeps listings for all heads call for availability

Stock Ford 240/300 rocker arm ratio is 1.60.
The Chevy 250/292 six 1.75 ratio rocker arms may be used for addition valve lift.


For valve lifts at .500" and above it is recommended to use roller rocker arms.
i have seen comp cams roller tip rockers used before not sure of technical specs or results part #1431-8


Scorpion 1059 roller rockers fit the 1985 and later pedestal mount heads. They are a 1.73 ratio rocker arm.

As far as stud mount roller rockers, the Harland Sharp are the only roller rockers that have the correct length for the proper geometry.
The distance from the center of the rocker stud to the center of the valve tip is typically 1.590"
The Harland Sharps are a smidge under 1.600" while the BBF and BBC rockers are 1.650".

The Harland S4002 are 1.6 ratio rockers that use the 3/8" rocker arm stud.
The Harland S4002-7 are 1.6 ratio rockers that use the 7/16" stud.

The S3002 series are for the Chevy straight six but also fit the Ford 240/300 six and are 1.75 ratio rockers.
The S3002 are 1.75 ratio that use the 3/8" stud
The S3002-7 are 1.75 ratio that use the 7/16" stud
The BBC and BBF roller rockers can be used

The problem with the BBC and BBF rocker is they are too long by .050" which means you have to position them very low on the rocker studs to get the roller tip to track in the center of the valve stem tip.
The rocker angle increases the roller tip travel from .020" (when the rocker sits 90 degrees to the valve stem at half travel) to .080" when the rocker sits low enough on the stud to center tip travel using the longer rocker arm. This as at .500" valve lift.

There was some thought about moving the rocker studs out to 1.650" but the BBC rockers have an acute angle with the pushrod if you raise them to the proper height on the stud and the angle becomes more acute with pushrod lift.
The reason for this problem is the 240/300 six valve stems and pushrods are parallel unlike the V8 engines where the pushrods approach the rockers at an angle.
The Harlands are straight across from the bottom of the roller tip to the center of the pivot point.

BBC Rocker

harland rocker


Flatout Gaskets offers a copper head gasket #911544060 .040 thick and #911554060 .050 thick
Both can be found at Summit.

{all images have been saved to fordsix gallery}
 
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81slantnosewp

Well-known member
now in regards to SI valves i actually contacted them recently and they directed me to vintage inlines here since they have exclusively received all their 240/300 products and although i emailed vintage inlines i never recieved a reply if anyone has those details particularly on SI hardened oversize valves i could certainly use that info
 

bubba22349

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With the 240 heads smaller combustion cambers when it's swapped onto a 300 short block it will raise the compression ratio around .4 to .5 to 1. Good luck (y) :nod:
 

BigBlue94

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I see one of my pics in there! It's the oval pushrod hole example, and all I can say is it's a 300 head, from a 240 in a 74 e100.

I bought the oversize valves from SI last year for my 85 head. I'll see what info I can dig up.
 

81slantnosewp

Well-known member
Appreciate any help including links to things mentioned like the current head projects your photo was the best example I could find of the oval pushrod holes infact if someone offers better photos for anything I'm more than happy to update the thread with them also I would like to keep a backup file of all photos incase the links ever break the photos are still available
 

F-250 Restorer

Famous Member
There was just one odd head that was not mentioned: Some 1982 300 heads had ridges in the combustion chambers. No one to this point has been able to explain why or in which models the ridges were found.

gTbawb3.jpg


B6JN5Fb.jpg
 

81slantnosewp

Well-known member
Hmm I'm assuming the photos you posted are those with the ridges id like to see some comparison photos as it looks as though the 300 head I have pictured might be the same as the one you posted
 

81slantnosewp

Well-known member
altered the wording to avoid confusion I was aware that it never left the R&D facility in any application and i also mentioned that there were two versions created if I'm not mistaken I think i recall you were the one to share that information in another thread
you currently possess one cross-flow head correct? and the other version would be even more difficult to find if at all
I'm curious as to how many of both were actually made and where they would be currently
could build a registry list for posterity and if any manufacturer wanted to recreate one they would have access to them
 

guhfluh

Famous Member
F-250 Restorer":2diu95j5 said:
There was just one odd head that was not mentioned: Some 1982 300 heads had ridges in the combustion chambers. No one to this point has been able to explain why or in which models the ridges were found.

gTbawb3.jpg


B6JN5Fb.jpg
Looks like a normal chamber to me. I don't see any ridges.
 

pmuller9

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Flatout Gaskets offers a copper head gasket #911544060 and 911554060
Both can be found at Summit.
 

BigBlue94

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pmuller9":5r0etx1y said:
Flatout Gaskets offers a copper head gasket #911544060 and 911554060
Both can be found at Summit.

I recently bought a Flatout gasket for my int/exh manifolds. Its thinner than the remflex, but doesnt squish like the RF either. And it came packaged much better, so I didnt get 2 damaged ones before I finally got a good one, as I did with the RF.
 

old28racer

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BigBlue94, can you post the number for the intake/exhaust gasket from Flatout Gaskets so we have both the head gasket & int/ex numbers for future reference.
 

pmuller9

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Both those rocker arms are for the Small Block Ford and are too short.
The fulcrum length is unique to the Ford 4.9 six at 1.60"
Only the Scorpion 1059 rockers are designed to fit the Ford 4.9
 

BigBlue94

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old28racer":qtjslmwh said:
BigBlue94, can you post the number for the intake/exhaust gasket from Flatout Gaskets so we have both the head gasket & int/ex numbers for future reference.

FOG-8085S

https://www.summitracing.com/parts/FOG-8085S

I'll add that the port sizes match up perfectly with my 85 head. The gasket is physically larger than the remflex, having more material on the outside perimeter. I had issues with the remflex not having enough meat around the ports. In fact, I burnt one part out from it not sealing against my header flange. I ended up welding a couple beads around that specific port and grinding them flat to the flange.

I was not very impressed with the remflex for that reason. I suppose with a log or efi manifolds ot would have been a bit better. Once I got it sealed up though, I had no leaks.
 

65 F-100 pete

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Supporter 2021
Hello all, I need some advice. I have a '65 F-100. It has the faithful 240 in it. I recently put a pair of cast iron headers on it. What a big difference just doing that has made! I am wondering if I were to have the head ported & polished if that would be worth the expense?
I am so impressed with the motor's performance now...would I notice much difference with the p&p and the larger valves?
The head has 89,000 miles on it. Three cylinders need valve guides replaced. (oil on plugs). Since I want a valve job...
Want to keep the stock rocker arms/pressed studs. Just want the motor to breath.
Thank you for your knowledge/experience. Pete :)
 
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