If you just dump on the 4 barrel and all the other stuff and if your car has 2.76 gears you'll get the same disappointment most V-8 guys get when they dump performance stuff on their stock engine a bog on take off or the low end...
Personally I dropped the shorts on a 318 powered 1972 Duster at the stop light a couple years ago with a bone stock 1 barrel slant six because I had a good 1st gear ratio in my 3spd manual and 3.21 rear gears...(and still was pulling in 21.5 mpg)...
You'll want to 'match' all the components and make the power band more useable to you at your normal driving habits. Heck if you want some pep and keep your mileage along with using the stock cam, you can go to a super six and use a 2 1/4" single pipe and that will be ok too...the drop-off occurs when you plunk $1000 for an intake a 4 barrel carb, tuning the carb, kickdown linkage, headers, exhaust work,cam, then find you'll then need to plunk another $500 for the stall convertor and a set of 3.XX:1 gears to make up for the bigger cam and then maybe even a few more $$$ to get the 8.25" rear to hold up to the extra HP you just made with the ad ons....
Sorry to say once you 'pep' it up keeping your foot out of it becomes very hard to do....(not sure why the 1 barrel car sits in the shed while the 4 barrel Hpak car gets driven daily
)Wait for a few others to chime in before making an educted decision about which path to take.
-D.Idiot