How can I get 300 hp to the ground?

[7000rpmisheaven]

I'm a beginning do-it-yourselfer. My goal is to get 300 hp to the ground. I know that it is not about buying the most expensive parts as it is about having the right combination. My problem is that I lack the experience to choose the right combination. I also have a limited budget.
Here is what I have:

85 GT 4bbl hyd. roller cam
K&N Filter
Flowmaster 2Chamber
Offroad H-pipe
Performer Series 289intake and 600cfm Carb
Stock ignition timing (about 12deg. i think)
compression with stock heads is 8.4
(since blowers might be too expensive this is a problem)

On the Way-
1 5/8" headers
MSD igniton (unless someone reccomends something better)
3.73 gears

The only thing I won't do myself is the machine work. I lack the equipment. My biggest question is what cam and head setup will give me the power I am looking for. Should I port what I've got or get a different set of heads. And then what would be the best cam to go with it.