buy a complete engine if you can...otherwise it's mostly about the heads cam and intake...AFR or Trick Flow heads, an Edelbrock Victor Jr intake and comp cam will have it rockin...long tube headers, suspension and fuel system upgrades will be needed, finally you need a great tune to pull it all together...
You might consider looking for a built car and selling what you have since the cash burn on builds is sobering
1995 Mustang GT Cnv 427 stroker
1996 Cobra with Kenne Bell 2.1 Supercharger dynoed at 12psi: makes 412whp/424wtq on E85: 250K miles on stock engine
2003 Infiniti M45 V8 340 hp
"What do you do besides drive fast?" "Have fun...."