House of Windsor 4ever!
I thought there was an adapter that would mimic one hub or the other, in this case, fit a Ford hub and provide a GM center. If done right, I think it'll be not only good, but actually great. But, if you don't want to go that way, the two front tires can become your rear spare tires, and then carry two of the tires off the Ford axle for front spares. Win win either way.