Very tough news after putting so much into it. I don't know where you can do better on the block price, but if you're at that amount anyway, how about getting a rebuilt motor instead? I've read about other guys who start on something like this, and keep on digging a deeper hole for themselves. I know it's (really) hard to have to eat what you've already spent, and then fork over an even bigger pile of $$. But unless you have lots of rebuilding experience, getting a rebuilt with a warranty might be your best option at this point. Good luck with it, regardless of which way you go!