I trying to install my damper and have been told that it should be a 3/4" bolt fine thread. But that bolt is too small . . . any idea what size it is?

You can press the crank pulley onto the crank and leave it that way to get you through, and simply install the crank bolt later. My engine had the threaded hole, but never had the bolt in it, and it survived for 34 years

I agree having the bolt head there to help you bar the engine over is a nice convenience.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

You aren't by any chance using a bolt that takes a 3/4" wrench are you? If you crank's threads are larger than 3/4" fine, someone has stripped it out once and redrilled and tapped it.

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Official Cookie and Mater Tormentor.

That's right, the 3/4" measurement denotes the diameter of the bolt's SHANK, not the wrench size.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.