difficult compared to a b series swap, yess, impossible, no......hasport makes a b-series to h-series mount kit, and they've also come out with a kit, to use the b series cable trannies on the h series blocks..its an adapter plate of some kind..also there in the process of making a new mount kit, so the oil pan doesn't sit so low in the ef's....
there are alot of good things about the being able to use the b series cable tranny, 1. b series axles, 2. a dime a dozen, 3. better gearing ratios than the h22 hydro tranny, and 4. the h22 hydro tranny is what makes the h22 swap so much heavier.