My $.02 worth;
Considering you want to keep the rpm level down, I would skip the rectangle port heads and save them for another project where they would probably be better suited.
A good set of oval port closed chamber heads with valves upgraded to 2.19-1.88 and a good bowl blend would work great for what you're wanting to do. I know a lot of people tout the open chamber (781/049) versions, but I've personally found the closed chamber units to work quite well. The closed chamber heads offer several benefits over the open chambers such as having two quench surfaces (which helps avoid spark knock [detonation]), and it takes a much smaller piston dome to achieve a decent static compression ratio. I would shoot for 10-1 to keep things simple & happy on 91 octane gas.
I would personally skip the hydraulic valvetrain and at least run a solid flat tappet. If you're set on a hydraulic cam, I would make it a hydraulic roller, but I doubt it would be worth much (if any) power over the flat tappet, which means unnecessarily spending $$$ that could be better spent elsewhere.
I would have normally recommended one of a few Crane grinds, but since they're temporarily on hiatus, I would look at something along the lines of a Comp 270S, 282S, XS274S, 143S (Comp's version of the GM 143 LS6 cam), or even one of the new blueprint 143 cams from Rob Clary if he has any left. If he does, follow his advice to a "T" in regards to degreeing it in.
EDM lifters are a must!
You can get away with running a rectangle port intake on oval port heads, but given the plethora of quality oval port intakes available today, I would recommend either a Weiand Stealth or Edelbrock Performer RPM. As far as a carb, a well-prepped Holley 3310 780 would work great on this. You could run a mechanical secondary carb if you wanted to use one here, but I doubt there'd be much of a difference in performance unless you went to one of the new HP series Holleys, but then you're sacrificing the ability to use a choke set-up (should you desire one in the first place).
I would wrap it up with a set of 1 3/4" primary tube headers with 3" collectors and a full length 3" exhaust system behind it.
Assuming the car itself is set up properly, this would be an easy 11 second combination and would be about as fussy as an anvil.
Again, just my $.02 worth.
Eric