Velobase does confirm that the early 70s Mighty Comp crank fits an ISO taper.
Miche Primato bottom brackets have ISO tapers. I can only find 110 or 115 spindle lengths, so you could possibly add spacers to the drive side or get the longer spindle. Here is a 68x110 for $23.96
http://www.amazon.com/Miche-Primato-...8782981&sr=8-1
Is this what your cranks look like?
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