The conversion has been done, and I'm told it is not bad. Apparently the frames are fairly close to the same. You should be able to search out some posts (here or CK5, dont remember which) where this was discussed. Worst case, IMO, is unbolt the 2WD front cradle, fab a 4WD type cross member (needed anyway for cross-over), mount front spring mounts (donor or simple fab), and rear shackle hangers (plus here is you can locate them better than the factory did). No problem at all, and much simpler than all the poor saps who have to change IFS 4WD to SFA!!!