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Old 04-30-2019, 10:22 AM   #1
35FORDOR
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I have a flathead 24 stud with just an A? Looking for any info.

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Old 04-30-2019, 02:20 PM   #2
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Default Re: A heads. Can anyone identify a head with just an A?

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I have a flathead 24 stud with just an “A”? Looking for any info.
"A" heads began to appear on the 1939 Ford 85HP models. Early production had the "A" located between the two forward most spark plug holes. Very soon thereafter, the "A" was located between the center pair of spark plug holes.
The engineering drawings always depicted the latter location so why many heads were produced with the "A" forward remains a mystery.

These heads were used through the 1941 model year.
The left 1939 head can be identified through the water temperature sending unit threaded hole. It will have a lip for the capillary tube to seat against. In 1940, with the introduction of the electric sending unit, the hole is drilled and tapped straight through.
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Old 04-30-2019, 02:44 PM   #3
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Default Re: A heads. Can anyone identify a head with just an A?

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"A" heads began to appear on the 1939 Ford 85HP models. Early production had the "A" located between the two forward most spark plug holes. Very soon thereafter, the "A" was located between the center pair of spark plug holes.
The engineering drawings always depicted the latter location so why many heads were produced with the "A" forward remains a mystery.

These heads were used through the 1941 model year.
The left 1939 head can be identified through the water temperature sending unit threaded hole. It will have a lip for the capillary tube to seat against. In 1940, with the introduction of the electric sending unit, the hole is drilled and tapped straight through.
Mike, Gary Mallast reports the opposite to be true. He says, in the '38-'39 book, that the Nov '38 drawing shows the location being between the front two plugs. Heavy handwritten note in pencil soon after moved the location to the middle. He found no other drawings for '39.

Drawings and real life don't always agree, as production is not likely to stop and wait for a mechanical drawing to build what needs to be built. That handwritten note may well have been written on the production floor after the fact!
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Old 04-30-2019, 04:20 PM   #4
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Default Re: A heads. Can anyone identify a head with just an A?

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Mike, Gary Mallast reports the opposite to be true. He says, in the '38-'39 book, that the Nov '38 drawing shows the location being between the front two plugs. Heavy handwritten note in pencil soon after moved the location to the middle. He found no other drawings for '39.

Drawings and real life don't always agree, as production is not likely to stop and wait for a mechanical drawing to build what needs to be built. That handwritten note may well have been written on the production floor after the fact!
Hi Alan, Thanks for pointing this out. I stand corrected in part. I was in fact aware of that note on the drawing but it was very ambiguous in that it lacked some information. As I recall the drawing that depicted the "A" near the front was never released for production. However, we know these heads (obviously) exist in quantity.
I tend to believe production was ramped up prior to any engineering change.
Still, the heads with "A" near the front would have been very early '39. At least I think so
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Old 04-30-2019, 05:54 PM   #5
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Default Re: A heads. Can anyone identify a head with just an A?

They used those 81A or "Big A" heads for all cars so they only needed the A designation which was also used when the 239 95 HP engine came out. They made T heads for trucks to lower compression but eventually they made purpose cast heads for the 99 series engines too but it took them a while. It wasn't long before they had those special high compression heads available as well. Making the larger displacement 95 HP engine sort of opened a can of worms at Ford.
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Old 05-01-2019, 11:50 AM   #6
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Default Re: A heads. Can anyone identify a head with just an A?

wow, lots of info. I am just starting to research my flathead and 27 t coupe build....i am behind the curve for sure. I will learn just so far lots to take in. Thanks Everyone.

Any help forthcoming is appreciated i will be posting lots of questions i am sure.
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Old 05-04-2019, 09:42 PM   #7
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Default Re: A heads. Can anyone identify a head with just an A?

It is my observation over many years that the 38 motor with 24 studs and the very early 39 motors had only the part numbers and Ford script, no A anywhere. Phil
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Old 05-05-2019, 12:20 PM   #8
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Default Re: A heads. Can anyone identify a head with just an A?

Casting procedures were always in a state of flux. Changes were made as engineering recommended and corners were cut whenever it would save time & cost of materials. Ford added the Mercury line with the 99 series blocks in 39 so changes had to be made a lot in 39 thru 41. I imagine all that casting stuff kept Charlie Sorensen and his people in the foundry pretty busy. That all was nothing compared to the changes that happened in late 41 and 42.

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Old 05-05-2019, 12:40 PM   #9
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Default Re: A heads. Can anyone identify a head with just an A?

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It is my observation over many years that the 38 motor with 24 studs and the very early 39 motors had only the part numbers and Ford script, no A anywhere. Phil
My 39 engine has an A on left head between the front 2 plug holes. It has part no. 81A 6050A and no ford script. Right head has an A in the middle with script below it. It has no part no. Engine had a tag that stated Reconditioned by Ford Motor company. My 38 engine has no A heads. Mark
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Old 05-05-2019, 01:19 PM   #10
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Default Re: A heads. Can anyone identify a head with just an A?

See post #2. "A" heads were introduced in 1939.
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Old 05-05-2019, 02:24 PM   #11
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Default Re: A heads. Can anyone identify a head with just an A?

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My 39 engine has an A on left head between the front 2 plug holes. It has part no. 81A 6050A and no ford script. Right head has an A in the middle with script below it. It has no part no. Engine had a tag that stated Reconditioned by Ford Motor company. My 38 engine has no A heads. Mark
If it is a true right hand head, you may find the part number at the rear of the head on the intake side. You can see it better from the left side of the car. The head should have a part number 81A-6049(maybe with a suffix "A" as well)
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Old 05-06-2019, 07:03 AM   #12
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Default Re: A heads. Can anyone identify a head with just an A?

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If it is a true right hand head, you may find the part number at the rear of the head on the intake side. You can see it better from the left side of the car. The head should have a part number 81A-6049(maybe with a suffix "A" as well)
You are correct, no. is there. I wonder why it is in a different spot than the left head.
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Old 05-06-2019, 07:47 AM   #13
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Default Re: A heads. Can anyone identify a head with just an A?

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Hi Alan, Thanks for pointing this out. I stand corrected in part. I was in fact aware of that note on the drawing but it was very ambiguous in that it lacked some information. As I recall the drawing that depicted the "A" near the front was never released for production. However, we know these heads (obviously) exist in quantity.
I tend to believe production was ramped up prior to any engineering change.
Still, the heads with "A" near the front would have been very early '39. At least I think so
My 39 engine came out of an early car, has a headlight fuse instead of circuit breaker. Mark
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Old 05-06-2019, 08:36 AM   #14
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Default Re: A heads. Can anyone identify a head with just an A?

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You are correct, no. is there. I wonder why it is in a different spot than the left head.
When the heads are installed correctly (left vs. right) the number will be close to the firewall. If it is forward, near the fan, that head is on the wrong side.
These cylinder heads were in fact dedicated to one side or the other.
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Old 05-06-2019, 08:39 AM   #15
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Default Re: A heads. Can anyone identify a head with just an A?

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My 39 engine came out of an early car, has a headlight fuse instead of circuit breaker. Mark
The headlamp fuse (design) was utilized throughout the entire '39 model year. Having witnessed that in the donor car you mention is not indicative of production date.
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Old 05-06-2019, 07:05 PM   #16
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Default Re: A heads. Can anyone identify a head with just an A?

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When the heads are installed correctly (left vs. right) the number will be close to the firewall. If it is forward, near the fan, that head is on the wrong side.
These cylinder heads were in fact dedicated to one side or the other.
Thank you, Kube! This is good to know. I knew my set of 'A' heads had different part numbers but never knew which went where.
Where did you find that information, if I may ask?
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Old 05-06-2019, 07:37 PM   #17
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Default Re: A heads. Can anyone identify a head with just an A?

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Thank you, Kube! This is good to know. I knew my set of 'A' heads had different part numbers but never knew which went where.
Where did you find that information, if I may ask?
You asked the million dollar question!
I have spent more hours at the Benson Ford Research Center than I am able to recall. The place is fascinating to say the least.
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Old 05-07-2019, 06:40 AM   #18
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Default Re: A heads. Can anyone identify a head with just an A?

An additional feature of some of the early A heads, with the A centered on the head, the RH head 81A-6049 has just one threaded hole forward and next to the radiator hose connection. This hole is for the heater valve. It is threaded through the casting without a lip. Later A heads have two holes one forward and one rearward of the radiator hose connection.

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