Technical 81A crank bearings

I bought a 81A engine.
I think its a 1938 ( 85 HP )
Its sleeved std and has 24 head bolts.
The crank had the rods grinded 040 and main was grinded 020 if std mains was 2.499.

Good news block is not cracked and I know how hard it is find a good block.
Some questions ;
On bearings, is it the same mains as to a 39 engine or as the 21 stud 85 HP, and are they aviable at 030.
-I saw MAC sell main bearings but only 21 stud 85 HP ( maybe the same ? )

 

I think they are the same because early 24 stud uses same guts as 21 stud
I own also 1938 24 stud engine.
Any serial numbers stamped on your block?

 

I may be mis reading, but with .040 and.020, why hunt for .030 bearings?

 

Don't mess with an early crank. If you don't care about having a 4" Merc crank, you can find a nice 49-53 Ford crank and rods for cheap, and the rod bearings will be easier to use insert kind, and cheaper. Everybody wants Merc cranks so the Ford cranks are almost giveaway prices. And you can probably find one that will clean up at 10/10.

 

But he's in Sweden.

 

The rod journals of the crank he already has are at 40 now. If they need more grinding, that crank is almost unusable. Even if you are across the pond from the Home of the Flathead, you shouldn't throw good money after bad.

 

Agreed. I've never heard of .050" under bearing. If you don't want a stroker, get a Ford crank. As Alchemy said, they are as common as cord wood and often, quite literally, thrown out.

Heck, if you don't find one and want to pay shipping, I'll give you one.