Motorcraft 5W-20 full synthetic goes in mine. I'm convinced it uses less and protects better than blends. I also use full synthetic tranny fluid because I think that's just as important. The fluids are always changed by the Ford dealer, and especially before towing on a long trip if it's getting close to change time. It's expensive but I have better peace of mind.
I'm very sorry to hear about your motor, but your cost is an investment too. You'll have a better motor that will likely have much more life left in it, and you'll save much more than 6 grand in a year just by not having a new truck sitting there depreciating. I'm all for repairing a vehicle rather than trading, that is if it's still what you like. I think it's smarter money in most cases.