THe last time I used my HiLift jack, the handle about took my left ear off, and made me see stars!!! If only one side of the frame horn is bent and the bend is only right on the end where the core support mounts, you might fix it using the jack between the frame ends. A large sledgehammer may also straighten the end back out. Heating up the framehorn with an oxyacetylene torch will help. A come-along may be useful if you have a good anchor point to hook it to. If the damage is further back, nearer the front axle mounts, I would be more skeptical about a self-repair job, since you can affect the alignment or crack the frame. IF the wreck was bad enough, it may have cracked the frame at the front crossmember mounts or the steering gear box mount so check those areas closely.