As one poster said, it all depends on what your trying to achieve. But to maximize what you already have - go with 275 tires all around, if it won't take 275's on the front - stagger them with 255's on the front and 275's on the back. That should set you back around 12-1500 depending on the tires. Then, perhaps some headers (short for low to mid range power, or long tube for higher range horsepower (and better exhaust scavenging) which will cost around 13-1500 minus install. Finally a 274 or 270 Comp cam, which will run around 4-500 without installation. Get it professionally tuned. That should do it - maybe an after market exhaust if any money left or down the road. You might be slightly over your budget - depends on what they are charging to install. Good luck.