A good 4bbl dual plane intake, a good set of headers, a decent cam and a good carb.
I had a relatively simple combo that consisted of milled and small portwork 68 302 4V heads, with a crane blazer cam (don't know the specs off hand, but relatively mild by todays standards) A Performer RPM intake, a 650 Demon carb,a set of hooker 1 5/8 headers and 3.70 gears through a 4 speed the car went 12.60's @ 108.5.
750 cfm whether it be vaccum or mechanical is stupid and not needed on a 289 cubic inch motor. i don't care if your are reving it to 7K. A 600 vaccum secondaries carb is ideal, even though it is a tad on the big side. I am really a fan of the demon carbs and mechanical secondaries, but that is just me.
A set of 1 5/8 headers will be fine. IF you want alot of lowend torque, go with a set of Tri-Y headers They feature 1 1/2 stepped to 1 5/8 then up to the collector. They give the best of both worlds for practical street driving. Also, you don't want a large carb if you have an auto with mild or stock stall speeds. Take everyones advice and stay with a sensible carb