21 Stud head puzzle...

Gary-UK

Gary-UK

Senior Member
I picked up a pair of *68 pump in head heads a while ago. I was intending on running them on my fresh engine. They were quite crusty when I got them so sent them straight for cleaning, pressure testing and a skim.

After they came back I noticed a few differences 'between the two heads, to the point I decided that they were actually different compression ratios and didn't use them.

The right hand head carries the raised part number 68-6049B along with the date tag of 12-9-48 and some kind of time indicator.

The left head carries a sunken part number of ( I think) 68-6050-B and Ford USA (the right doesn't have this). This head also has a date tag but it is on the inside edge next to the machined face of 3-10-47

When viewed from above the left one has much deeper pockets around the plugs when compared to the right and the combustion chambers are different depths and shapes. There are differences in the sizes of the coolant holes between the centre cylinders too...

So why were they producing *68 21 stud PIH heads in 47/48 and were the different comp ratios or are they the same, Just different shapes?
 

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Hey Gary
Can't really help you with an answer mate but as you know I switched to some Orosco heads late last year. When I took the old heads off my 33 motor I discovered they were different too especially the combustion chamber design...strange...
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gavin m said:
Hey Gary
Can't really help you with an answer mate but as you know I switched to some Orosco heads late last year. When I took the old heads off my 33 motor I discovered they were different too especially the combustion chamber design...strange...
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is the head in the lower photo for flat top pistons
 
I believe both heads are for flat tops. Thats's what I have in my motor.
Just thought it was strange that my heads had similar differences to Gary's ie combustion chamber, depth of plug pockets and coolant holes.
 
Because the cam is offset to one side of the block. Not in the center of the block and lined up with the crank. This makes the angle of the valves not the same on the lift and right sides. Look and you can see (with the heads off) that one side the depth around the sides of the valves are deeper on one side than they are the other. THIS MEANS THE HEADS are MADE THIS WAY ON PURPOSE. TO KEEP THE COMPRESSION THE SAME ON BOTH SIDES OF THE BLOCK. This makes up for the different angels of the valves. I hope this helps. Eddelbrock heads are built with a right and a lift head for this reason. Lyle
 
Gary, In my quest for dome top heads I ended up with a pair (thanks to Neil in Fredonia) that have the recess in the center like the lower one in the picture. I had 2 iron dome tops already but they were for the same side, right hand, and like the upper one in your picture. I am ready to shine them up & put them on, as long as they are the same, maybe try to CC the chambers for kicks but won't matter as long as they are the same. Looks like the non-recessed dome you have is the left hand, if you were next door you could have one of the matching ones I have.
 
The really curious thing is that the spark plugs are not located the same from one head to the other.
 
Please some one tell me If I am wrong. One bank of a flathead will not have the same cc as the other.
 
The chambers of the head in picture number 4 of post number 1 look more modern for the later type pistons. The chambers in picture 5 of that post are more like the older style. I know FoMoCo was changing from steel pistons to aluminum back & forth in those years. This is an interesting thread for me because I wasn't aware that Ford was still making the 21 stud pump in head types that late in the game but I think they were only in the UK since the 21 stud types were manufactured longer there.

My observation on heads seems that FoMoCo was dating most of the replacement heads but many of the originals on the various types have a casting number near the same locations as replacements but they don't appear to be a date. I've noticed that mostly the UK ones have the time clock casting. I've never seen that on the US or Canadian types.

The chambers on the heads were cast differently between one side and another up until around 1945. The 59A and 41A heads are interchangeable from one side to the other. The early ones are not interchangeable but I think the "like" cylinder chambers on the old ones will CC out the same or at least pretty close to the same.

Kerby
 
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Kerby, The one with the 47 date tag is a Ford USA item.

The continued English 21 stud engine production which you are thinking of is the Pilot E21A engine which was pump in block.

I have thought about CC'ing them out of curiosity and might do when I get some time, I went for some Eddie Meyers in the end but it has bugged for a while as to why they are so different, also looking at them again today I would say they have different coolant capacities too.
 
I just put my hands on 2 sets of similar heads, along with the aluminum heads that came with my 21-stud. They are all being cleaned up with the help of Doug Walker at Joe Smith Early Ford here in Richmond, VA. Monday I'm dropping them off at the machine shop to be cc'd and we'll find out what the differences are.

Stay tuned.
 
Gary UK, and Gavin M both have 1 aftermarket head, they are the same casting, one just has the flycut for the piston dome ---that way the aftermarket company only has to have one casting --then it is only a flycut to make it fit domed pistons ---I think combustion chamber design took a back seat to cheap production.
 
Right is dated 11-19-45 and left is 1-7-46 . As you can see the chambers are the same side to side . I cannot see any good coming from using mismatched heads with very different combustion chambers . 21 stud heads are a study in themselves and there are MANY variants . This pair are what I refer to as aftermarket . Could be wrong on this but any way you slice it these did not leave the assy plant on a 36 ford . That i'm sure of . David J
 

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There are lots of NORS (New Old Replacement Stock) 21 stud heads out there. I got a pair several years ago from an outfit in Colorado who must have found a whole warehouse full of them. The quality was not as good as original ford heads.

Chris
 
David J said:
Right is dated 11-19-45 and left is 1-7-46 . As you can see the chambers are the same side to side . I cannot see any good coming from using mismatched heads with very different combustion chambers . 21 stud heads are a study in themselves and there are MANY variants . This pair are what I refer to as aftermarket . Could be wrong on this but any way you slice it these did not leave the assy plant on a 36 ford . That i'm sure of . David J
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David, I am assuming you believe they are not Ford heads because they aren't stamped, "FORD?" Correct? :confused:

One of the heads we are having cc'd is a mate to those in the picture with the sparkplug hole centered in the chamber. And, yes, the combustion chambers match. I'm skeptical of the mismatched argument as we found numerous sets of 21 stud cast iron heads with driver and passenger side.
 
What I meant is this type didn't exist when 36 fords were being built . I have quite a few pairs of these water pump type 21 stud heads - to include about 15 pairs of aluminum's and there are MANY different combustion chamber configurations but ALL are the same RH & LH if you are looking at actual pairs . I posted pics of 68- gennie type cast heads on the wanted forum in response to a wanted ad . The combustion chamber differences makes pairing up 21 stud heads challenging to say the least . If needed i can supply pics of PAIRS with numerous different combustion chambers but RH & LH are the same on all mine .
phartman said:
David, I am assuming you believe they are not Ford heads because they aren't stamped, "FORD?" Correct? :confused:

One of the heads we are having cc'd is a mate to those in the picture with the sparkplug hole centered in the chamber. And, yes, the combustion chambers match. I'm skeptical of the mismatched argument as we found numerous sets of 21 stud cast iron heads with driver and passenger side.
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CWPASADENA said:
There are lots of NORS (New Old Replacement Stock) 21 stud heads out there. I got a pair several years ago from an outfit in Colorado who must have found a whole warehouse full of them. The quality was not as good as original ford heads.

Chris
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do you have contact info on this company i need a set, thks bob
 
I'm taking three sets of heads to the machine shop tomorrow morning for CCing: a set of original '34 aluminum; a set of genuine Ford replacements; and an unmarked pair of aftermarkets. I'll post pics and information after I get the report from the machinist.
 
Bob , If excellent used condition is acceptable the pair in my above pics are surplus . Pulled them off a 34 motor with flat top pistons ? I would assume this lowers the compression considerably as the heads are for domed pistons . The 33-34 waterpumps will be kept as I use that type . Lemme know . David J
37ford4dr said:
do you have contact info on this company i need a set, thks bob
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