You just have to get your grip stronger, use the fat gripz on all your barbell exercises (bench press, military press, squats, rows). You may have to swallow your ego a bit and use less weight in the beginning, but your grip strength will increase and using the fat gripz will also help with the wear and tear on your wrists and elbows in the long run. You won't be able to use the fat gripz with heavy weights on pulling exercises, but you should be able to use an overhand grip for these for a few reps.
Best deadlift is 410 at 165 lbs. for 3 reps.