Newbie Super Six question

Yep, ESP47's advice is right. You need to plan out exactly what you want the car to do (or not do, or do differently than it does now), and figure out your budget in terms of money, time, and effort, before you start buying parts. Otherwise the car will become a "driveway monument" that never gets done and driveable.

And McNoople's absolutely right about the need to pay attention to your ability to stop and steer (and see, and stay put in the car, and lots of other stuff besides going faster). See here (and read all the links from it).

Can't recommend 4bbl or headers on a regularly street-driven slant-6. You'll pour gasoline money hand over fist out the tailpipe and spend your free time fiddlefutzing around trying to get it to run all the way right, from cold start to hot restart and everything in between. "None for me, thanks, I'm driving".

Dutra Duals, on the other hand, are yes.

A 2bbl swap is an excellent upgrade. Finding a factory intake and kickdown setup for reasonable money is growing difficult. You may want to do the See the parallel 2bbl setup instead, which involves modifying a cheap and common 1bbl intake and modifying your existing kickdown linkage to suit, or see this thread for kickdown options. Photo documentation of a very well done parallel conversion (on an early car with rod-operated throttle linkage, not the cable type you have, which is actually easier to adapt) is here.