Damage, I had a devious and cunning dream a few months ago. As my ambitions are loftier than my bank balance, I had this genius thought that you would try to go through the process to get your car engineered with the cammer and find it all too hard. With that, my perfect plan was for you to get so sick of the whole thing that you'd buy a Coyote engine and sell the cammer (to me!) for a small fraction of it's true value.
With the agro and carnage and outlay that you're now faced with, I'm glad this plan didn't somehow eventuate..!
In all seriousness though, it's a really difficult decision in front of you. Depending on who you talk to, Genesis, Coon and Pond have all had their share of porosity/casting issues. If you haven't contacted Jay Brown or Barry Rabotnik, I'd be interested to hear what they have to say.
Good luck with it. I'm looking forward to seeing the car come together again soon.