Technical Mystery (to me) 59 AB

I picked up a 59 AB flathead from a friend for my 33 Tudor sedan about a week ago, and I pulled the intake manifold, and heads, to inspect the bores and the overall condition of the block.
Before I took it apart, I did a garage floor compression test with a 12 volt battery and help from my brother. It had 125-130 in every cylinder, so I was happy about that. Anyway...
I found adjustable tappets, and close to perfect cylinder bores.
Also, it has home made looking water jacketed (cooled?) exhaust manifolds.
And these markings on the pistons, and valve relieves in the block. And input would be appreciated.

 

Don't know why I can't upload pictures, I've done it 100's of times here.
The pistons have stamped on them:
3 7/16, 1/8 LC

 

Wow that's a big bore. I had ond 33/8+.030 and the walls were paper thin. Cracked early.

 

Yeah, I don't know, it looks good, and it was a good running engine, according to the buddy I bought it from..

 

Must have been goin in a boat. I would have run it after seeing those compression numbers, just sitting on the floor. let the neighbors know you are still tinkering with cars.

 

Check the stroke, with a Merc crank (4" stroke) that seems awfully close to 302 cubic inches, but if that turns out to be a 4-1/8" stroke that's around 312". A very big Flattie! Any idea when or who built it??

 

1/8 LC {low crown} should be for a 4 inch stroke.

 

Yep, Merc crank in there. Healthy engine or was at one point. What was on it for an intake and heads? I'd like to see the exhaust manifolds if you can post it.

 

It has/had a stock intake manifold on it. I removed the timing cover, and I see no marking on the cam, so it's probably a stock cam, I guess.
It also has head bolts instead of studs. The heads are standard 59ab. I'm in Idaho right now, so I'll have to get pictures of the exhaust manifolds when I get home to Arizona.

 

Is it a 59L block?

 

I see a factory relief.

 

Where do you notice the relief at?
I’m not doubting you, but I don’t see it with the pic of the piston stampings.

 

I see it too, on my PC, on pic. Good eye there alchemy.

 

I'm thinking it's the shaddow of the block, on the piston, to the left of the 3 7/16 marking..

 

That's some sharp eyes to pick off that ledge in the block. I had to go back and look for it. I think @alchemy sees it correctly. I read that Ford didn't factory relieve the 59, 59A, 59AB, anyway that is how I heard it, something about soft casting? Truck block maybe? Or it was relieved after the fact. I relieved my 8BA when I built it, rather I paid to have it relieved.

 

No, I had an L block once, and I see no L on this one

 

I’ve got a couple factory relieved blocks but can’t remember what letter designations they are. Kinda think one of them is a 59 X or Y block. They are packed away in different locations so I can’t run out and look.

The factory relief is really simple, just the straight down notch. Doesn’t follow the edges of the gasket at all.

 

Now I can see it

 

With all the other "Hot Rodding " that has been done to it, I would really suggest checking out that cam ! you might just be pleasantly surprised...

 

Both my C59 blocks are factory relieved. So, were all such Canadian blocks relieved?