Thread: What year is my flathead?

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'46-'48. 3.1875" bore, 3.750" stroke, 239 c.i., 6.8:1 static c.r., 100 hp @3,600 r's. Removeable, hardened valve seat inserts. With heads off, check center water jacket holes in the block. Top hole should be triangular, center and bottom holes should be round.

Some 59A blocks were sold as replacement engines for pre-war 221" cars and had a 3.0625" bore.

Richard: Is that a truck tranny with the rod running down the side of the shifter?


Don

Originally Posted by Itoldyouso

Richard: Is that a truck tranny with the rod running down the side of the shifter?


Don

Not sure about that Don.

Don't worry about breaking the studs, they're better than grade 8 bolts. The problem might come when they are stuck in the heads, preventing lifting the head when the nuts are off. Sometimes you have to pull all the studs to get 'em off.
The 59A is the best flattie, with the possible exception of the Merc 255. When you get the heads off check real close for cracks. Don't worry about the one from the center water hole to the adjacent stud hole,they all do that and it doesn't matter. Any cracks in the valve seat area and cylinder walls do, though, and if the exhaust ports or valley have cracks, it's toast.
That's a truck 4-speed. That's maybe a good thing, because trucks were kept on the road longer than flathead cars, so the rebuild may be relatively recent. Rebuilders didn't mess with cracked blocks, so the chances are better that it's a goodie.