Interesting fact: If ENIAC was tasked with calculating the current Bitcoin hashrate, it would have to mass as much as the world's oceans and would require an earth's surface worth of solar panels to power it.
Provided you set the input block, the implementation shouldn't be too hard. You need an incrementing counter included in the input, some feedback that will stop it and a huge field implementing the hashing. Likely much less complicated than the drive presented here... but much larger.