build my 440 to 600hp cheap

IF your car is 3000 lbs, and you have a good convertor (not the $190 MP units..a $600 at least race convertor), running 4.56s and the 30" tire, you should get 120 mph with 500 real horsepower. That's assumming hood suspension, fuel system, etc. What are you running now? You will have trouble getting 600 hp from unmodified Edelbrocks. 500 is easy, 600 is IMO not possible without porting work. What is you budget? That is a much more accurate indicator of how fast you can go. the next biggest factor is, what parts do you already have? Is the car a race car or street car?