I have a 97 3500 2wd automatic with a 350 rear end and it pulls like a locomotive. I would like to have the timing bumped up. I have a trailer that weighs about 6000 lbs. I dont want to hurt the power but gain some milage. I am thinking 15 or 15 and 1 half degres. Where in Las Vegas would be a good place to go and how much should i expect to pay? Thanks BOB