Flathead block ID help

31pickemup

31pickemup

Senior Member
Hey guys I’m looking at a 41-42 flathead. It has a 29A on the heads which means 42 Mercury. But is there a way to tell if the block is a Mercury with the heads on? There is a J441 cast onto the bell. That’s all I see. Any help most appreciated
 

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41-42 block is nearly identical to the 39-40 block 81A but with a raised surface under the intake manifold. Look for other identifying marks stamped on the block surface around the intake manifold.
 
It may be a 1942 239 block but one thing there sort of indicates a wartime assembly and that is the small undrilled boss on the back of the block where an oil cooler or heavy duty filter add on could be tapped in. This characteristic is on wartime engines and post war engines but I'm not sure about 1942 civilian engines made before February 1942. Not all 59 series have the larger 59 on the back bell so keep that in mind too. The 239 engine was used in Mercury cars and some trucks in the 1941/42 time frame. During the war is was used a lot in production or universal carrier type track vehicles like the T16, mark I. They were also used in some Ford built scout cars. Most Ford trucks produced had the G series 6-cylinder engines but a lot of fire trucks were also produced. A good look at the cylinder deck will give some confirmation. There may also be some form of date code on the intake deck but that was not on all production.
 
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The Mercury engine I had was marked 99 on the intake deck next to # 1 cylinder. It was also painted dark blue.
 
The Mercury engine I had was marked 99 on the intake deck next to # 1 cylinder

That would make it of Canadian manufacture...the Canaks were ahead in many ways with their development of the flattie...their blocks are all readily identifiable year by year since the 36 LB engine. Takes much of the guesswork out of identifying what you've got.
 
31pickemup, To confirm what has been written above, that is most certainly a wartime manufactured block as evidenced by that extra boss amongst other features....and probably a 239...however, as you know, the only way to know for sure is to pull a head. Good luck, Brian
 
Ford stamped "99" on the engines in the first year or so of production to ID the 239 from the 221 for assembly purposes. The Canadian counterparts had a raised casting 99 mark on the front right on the ones I've seen. Ford US quit stamping them when they started painting the assemblies dark blue for ID purposes so they no longer needed the stamp to ID the assembled engines. The 221 engines remained the darker green color originally used for them. OD green would have been common for just about all war time production.
 
Thanks for the help guys. It has the 42 Mercury heads on it. And the block has the raised deck. If this is a 42 it wouldn't have the 99 stamp or casting on it so thats no way to confirm it. I guess im going to have to pay for a set of gaskets
 
You havn't stated what the asking price is, or if it was listed as a good running motor. That being said I would want to pull the heads anyway to check for cracks or other problems before I threw out too much money. Just sayn. Bill
 
A lot depends on what you want to do with it. If it runs as-is and is nice does it matter if that is what you want to do with it? Had a friend in the mid-'80s with a '71 Corvette. He loved the car, thought it was fast, and all that. It got to smoking and he tore it down to rebuild it. Turns out it was a 307 and not a 350. Then it was junk this and slow that. Until he knew it was a "pukey" 307 he thought it was a 350 4-bolt and it was great. Again, depends on what you are going to do with it.
 
its supposedly has been completely rebuilt. It was rebuilt in the 80's and put in a heated basement and that's where it has been ever since. Asking price is $2500
 
Just a bit dusty
 

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now the famous question, rebuilt by who, and what did they do? thats always the problem on these deals. i hope you get a good one
 
It does look nice and $2500 is a bargain for a rebuild but still; 30+ years sitting. Even in heated basement. How's the humidity down there? I personally would be scared to just drop it in and go. I would at least want to look at the bottom end. I would want to pull the heads and intake and see what it looks like inside. Does it turn? You may have found a great deal or maybe just a core. Does the place that built it still exist? So hard to know. Hate to take apart and re-do something that is good, but at the same time if its bad you could ruin it by running it if it wasn't built right to start with.
 
Place is no longer there. I did a google. Yes it rolls over fine. I have the full details of the motor. It was redone with .060 TRW 4 ring pistons. NOS crank, everything new. Only thing they put in it that’s not stock is adjustable lifters. When it arrives I’m going to pull a heads and the intake. I’m going to replace the cam and put a original slingshot on it
 
It was rebuilt in Beaver Creek Michigan by a man named Andy Warner. Owned a shop called Beaver Creek motor parts. Was a big flathead racer and builder back in the day. But that’s just stories.
 
The crab type distributor came on line in 1942. The later 59 type distributor was probably developed during the war so that is would seal up better than the crab. It has the dual crank sheave like a 42 thru 48. The Generator in larger than normal and looks to be a high output unit like a lot of emergency vehicles had.
 
rotorwrench said:
The crab type distributor came on line in 1942. The later 59 type distributor was probably developed during the war so that is would seal up better than the crab. It has the dual crank sheave like a 42 thru 48. The Generator in larger than normal and looks to be a high output unit like a lot of emergency vehicles had.
Click to expand...

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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