Any Ideas For Cheap HP For a 98 Cobra?

[98mustangcobra]

Well im looking to get my car to 500Hp - 600Hp
Also i know an 02 LS1 with the same basic things im getting but LESS and he has proof. A DYNO sheet showing he has 635 HP. Stock Block.
And a 5.0 with around 450 HP
Both Have no Superchargers or Turbo's

Ok. About my past. I am not that so to say smart on these different things that is why i have been asking all things on these boards. I have raced over 70 people all on the street in the past say 5-6 months. I have lost about 5 races because of people with alot more power than me or with NOS. I have only got my car because it is close to stock i have only hit like 140 - 145. That was the fastest so far which i want to go alot faster. I have to get the rods and pistons because I threw a rod and it messes up alot of things when that happens. So i am getting a kit so i will also have a new Crank and all of them hold 1000+ Hp. And while the engine is pulled i will be putting on the headers. Then while im at it i will get the offroad x-pipe and mufflers. All Bassani. Also i am getting the Heads Ported and Pollished because of having them off and it help with HP gain. Then last i am getting Under Drive Pulleys. Because it give a little Horsepower and i have heard it is a good item to get. It free's up HP.
The Rest of the things i am getting i will be waiting until later because they dont need the engine apart to install. or the engine pulled. So The Costly Things i am gettting are because of taking the engine apart to fix the Rods and Pistons and Crank. That is a lot of money and it has been taking me awhile to save. I still dont have all the money. So This is why i am looking for Cheap HP. And I will later on in a year get a SuperCharger or a Twin Turbo. But i can not spend that kind of money now.

So is there anything that you can help me out with to get to my goal HP? Without spend TOO much more than i already will be. Thanks and have a great day.