Check your rub rail. I have seen where caulking on the rub rail fails and the water runs along the rub rail near the bow, and enters the hull near the stern
Check all deck hardware caulking
Check you bilge vents
I do not have one, however I googled it and found one on a different iboats thread
https://forums.iboats.com/threads/omc-cobra-305-350-coil-wiring.773552/
again, any force strong enough to bend the crank would have busted the block.
pull the flywheel housing. then unbolt the coupler, inspect it. however as stated above, spend a few on a new coupler.
Your 'new-style' block is nearly identical to the older SBC. The crank, rods, and pistons are GMPP SBC parts in a Mercruiser supplied block
You are overthinking it