It's about 3/4" long with a 1/2"i.d. & 9/16"o.d.
I put quite a few of these small blocks together. Glad I'm not the only one that doesn't know were it goes. lol..
Think I had picked up the block before even dropping off crank or rotating assembly. So I dont think it belongs to the crank.
I already put on rear main cap I was wondering if maybe if it was a locating dowel for the rear main cap maybe where the oil pump/distributer shaft goes through to the oil pump.
Or
I'm thinking it may not even belong to this motor. Machine shop will be open tomorrow I will be able to call.