what is your goal with the car?
I have been building Pontiacs since 1987 and everything from a dead stock numbers matching build to a 8 second drag race car.
Do you want a car that you can just get in and turn the key and go and drive on the highway or just cruise around town once and a while?
I have built some killer 400 inch pontiacs using the original cast iron heads that just had rebuilt with new valves and springs and guides that would run pretty [censored] hard and beat most of the mustangs on the road.
Also have built many aluminum head 455 + cubic inch engines with roller cams....etc
I also have installed many EFI systems on cars and are quite familiar with all of them. Depending on which FiTech system you have and your current fuel system it may only good enough to support 400 HP at most.
What is your goal and your budget?