now what should i do?

You need to start with a new fuel pump 155 should be good if you don't plan on a forced induction setup.Then 24# injectors with adjustable regulator.You need a fuel pressure tester or gauge.Then get a b303 ford motor sport cam.Intake and throttle body should be done too.You might want the intake and throttle body before the cam because to get the engine to breath better it must have a easy way to suck it in.That is what a cam does is let the valve open longer and have some over lap so the induction pressure helps the exhaust better.Oh the posibilities are endless.That is a good street package I think.Check ebay if you don't want to pay sky high prices for the fuel parts I mentioned they have alot of that stuff.Almost forgot since you have the gt 40 heads maybe the gt 40 intake would be best.I have the performer 5.0 and it is a great intake made a huge differance when my engine was close to stck.That was one of my 1st upgrades with the throttle body.