Re: C&C 27 Project Boat help!
I agree with Faster on all accounts but the motor may be rebuildable. If not there are a lot of good used parts there.
The old Atomic bombs have a lot of metal in them and can be rebuilt even if there has been a lot of ware or neglect. Although, looking at the motor and not knowing what's wrong with it would lead me pull it out of the boat first. Jamming those punches in between the head and block was probably not your best moment as these surfaces have been machined to tolerances of a couple of thousandths of a inch. They will need to be resurfaced now.
Just a quick google found two Atomic 4's for sale in my local, one is a fresh rebuilt both are well under a thousand dollars and your old motor will be a good source of parts. That is something you need to think about for the future.
If you are still determined to get those bolts out heat works the best, but firing up a torch on a gas powered boat is probably not the best idea.
I would pull the motor and disasemble it in a clean shop and then make your decision to rebuild or replace.
We have three rules;
No bleeding on the sails.
No slobbering on the charts.