Cams and head work (P&P, valves,springs,retainers,etc)
high compression pistons or thinner headgasket to raise the compression
weight reduction
tuning......<------ big part....don't go with a cheap static chip, go with some tunable....even a v-afc would be better then a cheap static chip..
larger injectors.....just a few idea's
It's going to cost a pretty penny to get your car to run with 5.0's ....
in all reality you could build a turbo set-up for less money and beat them easier.......just my .002 cents.