I like your current setup pretty good.
If it was
my car I would run:
A hydraulic cam, 500 to 530 lift, 218 to 224 duration at .050, 106 to 110
LCA, maybe split the duration slightly to the exhaust ports. (splitting will roughen the idle, if you want to keep the stock converter, be conservative...)
1972-74 351w heads. Nothing special... the biggest expense would be machining for studs and plates. You will want to run full roller rockers and hardened pushrods. Use the stock valves with a fresh valve job, bronze guides, and good springs matched to your cam. Mill the heads .020", angle mill if you want a little more, but find someone who knows what they are doing if you go this route.
Pick your head gasket wisely. They range in thickness, use the thinnest you can find that is still a brand name.
You will need either swap washers or swap bolts to put the W heads on your SBF.
X-Cellerator, Torker 289, Holley single plane... IMO these are the best intakes ever made for mild 289-302 engines.
F4B or Stealth would work okay, but not as good from my experience.
Your carb is okay. You will need to retune with changes like you are contemplating.
The key to getting both max torque and top end power from an SBF are little tricks like:
Lower
LCA
Split duration favoring the exhaust
Lower gears (3.55-4.11)
Mild single plane intake
(the ones I listed have small plenums and tuned runners which are aimed at both torque and rpm)
Somewhat heavy spring in the secondary side of the Holley
Heavy on the timing
L/T headers
The SBF doesn't have the cubes that the cookie cutter 350-something engines have. The so called "rules" put forth by magazines and such, about dual plane intakes, small headers, etc... don't really apply. The tiny stroke of the crank just doesn't work the same. You must build in some gearing, timing, and make use of the durability of the short stroke crank... you have to plan on spinning these engines a little higher.
They are good for it, the short stroke doesn't have problems spinning where other engines need high strength components. Good rod bolts cure our only short coming when it comes to spinning a 3" or less stroke.
On a side note, the 289 has an excellent rod ratio... The extra piston dwell absorbs more of the energy of combustion than just about any other stock engine and the cylinder walls wear less with the tall rods. Meaning max power to the crank throw without needing accessories that are normally torque friendly.
Sorry so long... I get off on tangents when I talk SBF.
Good luck, and consider a loose 11" converter,
Dave