Crank bolt for 1968 170 slant 6 interchangeable

@RustyRatRod are you sure about that? I just tore down the slant in my 82 D150, it has the bolt.

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The new engine for the Valiant (bagged up) has one too. That engine came from a 79 D100 so maybe it's an early/late thing?

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The original slant in my 66 has no bolt, the slant from the 78 Volare has no bolt. Most peculiar.

To the OP, it is a 3/4 fine thread, 1-7/8" long. The washer is a beast, over 3/16" thick. A really good fastener place should have these in grade 8.