What would I gain from a 4bbl on a 273?

my father has a factory 273 power pack 4bbl intake and carb he would sell.he ran it on our 78 volare wagon 4spd.for several years.sold the car kept the intake.also have 4 sets of power pak valve covers in excellent condition but don't thing these are for sale.but i know he would sell the intake and carb combo.alson has original chrome? air breather with it..if interested u can contact him at 660-849-2580.his name is Danny.i am certain he would not part with the valve covers.hope this might help in decisions of stock or aftermarket.