Deadlift question (prop bet help needed)

[gordongecko]

I have a online poker buddy who is a pretty serious powerlifter, who also loves to make pretty much any kind of prop bet possible. I have taken him on pretty much any fitness related prop bet he has made (lose x ammount of pounds in x weeks, run a 5k drunk in under 25 minutes, etc.) This one is rather frustrating for me to take though. The deal is this.
He is giving me 2:1 up to 5k that I wont be able to deadlift 3 times my bodyweight within 3 months (I want 4-6, but he is willing to lower the requirements for a smaller time frame). As of I am on more of a HIT/bodybuilding routine, and pretty much stay away from deadlifts, and squats, but I have done them before. I can probably get up 315 right now on my dead lifts. I am weighing 165 right now, meaning I would pretty much have to get up 500 pounds to win this bet. I am not asking if this is possible (because im likely to take this better either way, it seems to fun to pass up, and gives me a reason to work on my deads, plus im a prop bet fish).
My questions really are just HOW can I pack on the most weight, safely within 6 months on my dead lifts, and what other lifts can I do to help improve my deads. The biggest problem I see is it will be hard to do this without gaining weight, thus making it even harder for me to win.
Any help is appreciated, but please refrain from berating my prop bet fishiness lol.