38 heads

Pandersen33

Pandersen33

Member
Anyone know if all the 24 stud center outlet heads are interchangeable? I have a 38 24 stud that im toying with some aftermarket heads on. However when browsing everything says 39 or later but im hoping thats because 38 used both 21 and 24 stud engines.
 
I think they are the same. The issue is most likely that 38s were 21 stud at the beginning of the production year and then the 24 stud engines were phased in for the later units. The supplies my not want to say 38 1/2.
 
Pandersen33 said:
Anyone know if all the 24 stud center outlet heads are interchangeable? I have a 38 24 stud that im toying with some aftermarket heads on. However when browsing everything says 39 or later but im hoping thats because 38 used both 21 and 24 stud engines.
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Your existing heads being 24 stud would possibly be identified by 81A prefix.
Phil NZ
 
The valve angles changed after the war so prewar heads have to be modified a bit in the valve relief area to work on the post war engines. The big A heads are good ones.
 
Not to worry. I am absolutely sure that Ford DID NOT change the head bolt pattern from late '38's to '39's. Count he studs and if you get 24 per side, you're golden. (21, you're out of luck, and 17 means you have a V8-60.)
 
Later 8ba 24 bolt heads are different.

Talking 59a down... I do a quick check on heads on shows. 3 bolts down the middle 24 studs. 2 down the middle 21 studs.

I think the only thing too consider being a 24 is maybe flat top pistons. Also you will need to replace the lower studs. You could mill the head also.


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I think sharp made aluminum heads that the lower studs didn't need to be replaced. If you are going for a little compression boost. Mill the iron heads. The cooling advantage or not... (more advantage with a cleaner block, which you can do with the heads off and a coathanger or long screwdriver roddin the block) and maybe weight difference... is not that much on a street stockerish.


by the way... just my opinion.
 
This is where we miss the great Mr Bruce Lancaster .
What I have read the 1937LB was the last of the 21 stud motors and had the doam pistons with inserts...
 
Flat's were done after 35. 36 was the first lb and a mid yr. But... anything is possible... 37blocks run to mid 38 when they ran out of blocks. Mostly trucks, last to change.


For early 21 bolt blocks the 37 is the best block with most goods. Cam and crank bearings etc.


Had heads for a 42 ford from h&h with flat pistons. 91a. Sold them both.
 
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The engine should have domed pistons and you should be able to run what are commonly referred to as 39-48 center outlet heads. The 24 stud engines came out later in 38, so it should basically be the same as a 221 cubic inch 39 Ford. Don't throw away the stock heads - there are folks who love the early 221 iron heads - due to the tighter combustion chamber (depending on what you have on it now).

I'm not sure if anybody is currently making an aftermarket aluminum head designed for the stock studs (the shorter lower ones). You should definitely check that out first - just so you know what you're getting into. It can be a chore removing the original studs and putting in longer ones - especially if you don't have an oxy/acet torch and have not done it a few times before. Also, if you break one off . . . the whole project just got a whole lot uglier - especially if you were planning to do this with the engine in the car and are not taking the whole thing apart. :)

Good luck!
 
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hop up said:
This is where we miss the great Mr Bruce Lancaster .
What I have read the 1937LB was the last of the 21 stud motors and had the doam pistons with inserts...
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Guess that depends on how you look at it. 1938 early vehicles had 21 stud engines and 24 stud engines appeared later in the production year. I'm not sure when the change over occurred, but several of the 38s I have had were all 21 studs. So, guess you could consider the 21 stud engines as 37 holdovers, but it is not commonly looked at that way as far as I know.
 
Im positive this is a 24 stud engine with center outlets. I just wanted to make sure there was no issue with waterways or clearance for some wierd reason since it is a 38 and all those heads called for 39-48.
 
Pandersen33 said:
Im positive this is a 24 stud engine with center outlets. I just wanted to make sure there was no issue with waterways or clearance for some wierd reason since it is a 38 and all those heads called for 39-48.
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Well, are you clear now, or is there still a question? Flatheads come in two general head configurations, 21 stud and 24 stud. Only real consideration with the 24 stud heads is the change in valve angle. I would think most aftermarket heads take this into consideration, but always best to check. Easy fix if the is any interference.
 
JSeery said:
Only real consideration with the 24 stud heads is the change in valve angle. I would think most aftermarket heads take this into consideration, but always best to check. Easy fix if the is any interference.
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I'm not aware of anybody taking it into consideration these days - but would like to know if somebody is.

Edelbrock used to actually produce a right and left head - such that the chambers were designed for the different valve angles as well as valve heights (to the deck). They also used to have a canted roof that was designed to match the valve angles . . . haven't seen that in any of their CNC produced valve pockets. Maybe some of their heads still use the old cast chambers . . . anybody know?
 
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