I've been searching for this but my situation might be a little different...
Basically I bought a used built-(6)shortblock and disassembled it and found a scratch on the crank

So luckily I have a spare 6-bolt crank that's in perfect condition.
BUT...The block is set up with ARP mains and the counterweights have been shaved(?) with this set up.
Can I just swap in the good one?
Thanks