Flathead block ID help

The crab type evidently had some problems so it was a one year only deal in civilian production. It is easy to convert to either to the late type used on the 59 series engines or convert them back to a crab. A lot of folks did his back in the 60s & 70s when it was easier to purchase the crab cap than the multi part 59 series type sealed cap. The 1941 was the last year of the helmet type but was the first year to have the 11A advance unit that ended up being the replacement part for most of the early V8 type distributors. It gave a bit more advance than the previous units did.

It's been a long time since that era and many things can get mixed & matched on these old engines. That makes it harder to ID what you have unless you look at the cylinder deck and see what shape the coolant ports are. The old 221 engines had a bit of a ledge on top of and just behind the timing cover at the front of the block. This is where the pencil test comes in. If there is no ledge, then its a later motor. Bulges on the side of the pan rails is another indication of the old blocks before 1941. There were core plugs in those spots on the pan rail to allow for easier removal of casting sand from the block during manufacture. There are a lot of subtle differences over the years.

The Barns photo ID thread helps. https://www.fordbarn.com/forum/showthread.php?t=25301&showall=1
 
The gent who had this was putting it in a 40 Ford. But never got around to it. So might have used some earlier parts, these things are so old parts get swapped out
 
31pickemup said:
So this should have a crab distributor? I didn't think the crab came out til 46.
Learn something everyday. Well it is a 42 by the raised deck and con-caved block between the exhaust ports. I'm hoping the 42 Mercury heads are correct. I probably wont be able to run that type of generator anyways. Ill have to run a earlier model with the fan/generator combo. That will all have to be decided during mock up.
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42 had a crab, 41 had a divers helmet (what you have) the 42 up cam in different and would need mod. so more than likely yours is a 41. I have the exact same motor, raised intake, no core plugs, divers helmet, blue paint except mine has the big (A) heads. never had them of to know if its 3 1/16 or 3 3/16 bore to know if its merc or ford for sure
 
I just checked my 41, the intake deck is flat. At first it looked raised, but it is the gasket. There are freeze plug bumps on the pan deck and the exhaust ports are raised up on the block. There is a cast-in no. on the bell housing ( 81-A) and the vin. no. is also stamped on the bell housing. There is an "A" cast in both heads and Ford script also cast in head below the "A", it sounds like I may have a mixture of parts. The engine supposedly was rebuilt and had about 500 miles on it when I bought it. I'm trying to get in contact with the man that did the rebuild and find out. The markings don't add-up to the info. on this post, Thanks for the info. anyway Good info. Al
 
Well I pulled a head it is a Mercury. Thank god. Everything looks good. Just needs a good wipe down from sitting for over 30 years
 

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Just got off the phone with the man that had my 41, he had the engine overhauled. He said the shop that did the work removed the sleeves and put larger pistons in it, also put a mild cam and new valves and seats. He doesn't remember if the lifters are adjustable or not. He said he put all the paper work in a bag and left it in the car, it was not in the car when I bought it (wish I had it ) I'll pull the intake some time and check it out. We talked a lot about all the old cars we had in the past and wished we had them back, real nice guy. He also said the heads were reworked, don't know what that work consisted of, milled or what. Al
 
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grumppyoldman said:
Just got off the phone with the man that had my 41, he had the engine overhauled. He said the shop that did the work removed the sleeves and put larger pistons in it, also put a mild cam and new valves and seats. He doesn't remember if the lifters are adjustable or not. He said he put all the paper work in a bag and left it in the car, it was not in the car when I bought it (wish I had it ) I'll pull the intake some time and check it out. We talked a lot about all the old cars we had in the past and wished we had them back, real nice guy. He also said the heads were reworked, don't know what that work consisted of, milled or what. Al
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Grumpy if your block doesn’t have a raised deck or a con-caved block between the exhaust ports it’s not a 41
 
Likely a 39 or 40 but it'll work just fine.

31pickemup
It looks like that motor is from a truck. Most of the truck 239 engines had that relief. The reliefs work well with aftermarket aluminum heads that have the crow foot shaped chambers. It's nice to have confirmation for certain.
 
rotorwrench said:
Likely a 39 or 40 but it'll work just fine.

31pickemup
It looks like that motor is from a truck. Most of the truck 239 engines had that relief. The reliefs work well with aftermarket aluminum heads that have the crow foot shaped chambers. It's nice to have confirmation for certain.
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Yeah I’m happy it worked out. The decking surface seams a little rough for my liking. I hope I don’t have a head sealing issue
 
Yes 31 that's what I think, maybe the original block was bad and the block was replaced. Don't know the CI or HP with the larger pistons, cam and head work. It never did seem like a stock engine to me, has to much HP to be stock, but with a 3:73 rear gears it would feel like it had more get-up and go. Al
 
31pickemup said:
Well I pulled a head it is a Mercury. Thank god. Everything looks good. Just needs a good wipe down from sitting for over 30 years
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Looks good! Keystone block, factory relieved . . . probably a truck or commercial engine. I used this same engine (1942 version) as the basis for my 284 cubic inch engine in my 32. There is a bunch of common folklore related to these 'keystone blocks being the thickest" and best to bore for racing - have not found that to be true (using a sonic tester). They have the earlier valve angles.

The deck looks like somebody sort of 'hand prepped" it with a big file. I'd check it for being true and straight - while you have the heads off. I say this because the marks in the surface are not in a consistent pattern/direction - as you'd have when a machine is used.

If it was mine, I'd replace all the gaskets and replace the oil pump with the later 49-53 pump and truck pickup.

Also - I'd pull the main caps to check the condition of the crank and bearings and see if there is any good lubrication in them (that isn't all coagulated and dried up). Same with taking two adjacent rod caps off, pulling the floater bearing halves and checking a rod throw. Given what you find, it would probably be a great idea to disassemble/reassemble the engine with new assembly lubrication on all the critical surfaces (including the cam).

This should be a great start to a fine engine . . . good luck!

D
 
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According to Van Pelt's spec. sheet info. the early 41's had a carry-over of the 38 style blocks, and had a flat intake surface. Also had the freeze plugs showing on the pan rail, With the casting on the bell housing 81A. So my engine is an early 41 by his spec. sheet. Thanks for the replies, made me dig further for engine blocks. Al
 
The war was starting to put a crimp on things in late 1940 due to Canadian involvement in the war effort. Since Ford US was shipping in their iron resources from Canada, it stood to reason that the resource was going to start having limitations. The 1941 change started early in the model year but like any of these type changes, the old stock still has to be depleted before new stock inters service.

If your 1941 was an early serial number, it could have been built up with an earlier type. If it has a number in the middle of the range then it's doubtful. It could have also had an earlier type installed for an engine exchange overhaul. It's been a long time since 1941 and any of those prewar engines with a long snout crank will easily fit in the car.
 
Thank's rotor, where would the engine serial no. be located? There is the vin. No. stamped on the bell housing, I have found no other no's, except 81A cast in the bell housing. The engine is in the car and hard to see any other places. The engine vin. matches the body vin. no. is there any other place to look. Also 8B 75 is stamped into the upper firewall. Al
 
Everything is based on the VIN or frame/transmission ID number. Transmissions can be replaced but if it falls in the 1941 range of numbers and it's on the title or registration paper then that be it. Engines serialization was called for in some states during certain year ranges but those numbers would likely have been done at the dealerships in any affected state. It is uncommon to find the vehicle ID number on the engine in the early Ford cars. GM did that & maybe others and it led to a lot of problems due to replacement engines being installed.

Mac VanPelt has a good list on his site. http://www.vanpeltsales.com/FH_web/flathead_serialnumbers.htm
 
Thanks a bunch Rotor my no. is in the first half of the production no's. that would be in line with VP's explanation of the difference in what year my engine is. Having the flat intake surface and freeze plugs, it was carry-over engine. Because as you stated earlier the war was on the horizon and everything already produced had to be used. Al
 
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