Setup trumps power more times than not. Adapability to different conditions and the ability to read the track will also get you further than any amount of power. If in a points race, consistency is key.
First off, are you pulling once or multiple times? Sounds like you just have one pull you want to beat the 12v's at, that wont be hard. Most people get hooked and do it a lot, most of the reccomendations in this thread have been if you plan to make 10+ hooks in a year. Have to decide how many of the mods are worth it to you.
Pulling is all about reading between the lines. Not about cheating, but about making yourself able to compete with the others who read between the lines. "Reese Style" simply is trying to keep people from hitches that transfer the load more to your advantage, it basically means any hitch that bolts to the rear of the frame rails with no supports running to the axle. They generally want it sticking past the rear bumper also. If you do not already have a pulling eye, get one. Needs to be 3x3.75" for most of the newer safety hooks and 1" thick, not thicker than 1.25" though. double check, hooks may have changed since I last built one.
You wan't bump stops. Just weld recievers onto your reciever like shown in duramaxak's picture, then they are removable.
Do they give a minimum suspension travel or simply no suspension stops at all? Clamping the overload springs may help some. Many places just require some travel, but if thats not an option then thats the way it is.
Get some different tires and rims, looks like you have some big rims now, get some smaller diameter rims and as mentioned STS, BFG AT or duratrac's all seem to be good. Use them just for pulling so they keep their edge.
If weight is not allowed up front, put a bunch in the cab. Some places require it to be "secure" for safety, but they shouldn't outlaw it all together, need somewhere to put weight on the chevy. Afterall the Ford's are the only reason the weight limit is 8500lbs. Don't get too carried away stacking weights in the bed, too much in the wrong spot can hurt you too. I beat many turds weighing 8500+ when I weighed 7000lbs.
1800 stall is pretty low but it is what it is, you're not trying to light a huge charger.
Otherwise just keep it to the floor and have fun.