Engine opinion You know how it goes........

[8door]

Here I am working on my 68. Was going to replace the wood bed and paint the truck and drive it. Now I have installed a later power steering unit and have the front wheel wells out to look for rust ( there is none)and all the chrome etc stripped.
Looking to do Vintage air so pulled old heater motor and stuff.Radiator out.Get new wiring and on and on. Well you know how it goes.....
Got boxes full of baggies with nuts bolts screws etc labeled of course.
Sitting here looking at the engine. Not original it's a mid 70's 350 with Qjet coupled to a th400.
I'm this far maybe I should pull engine and rebuild it.
The 68s came with 327 not 350. What do you guys think of going back to a 327? Do they have about the same horsepower specs and what about economy,a 2 barrel carb as compared to 4 barrels.?
I guess what I'm asking , is there much difference between the two?
Are 327s available?