Did the 340 really make 275hp?

Small chnages can mean alot. Mopar Muscle did a series of builds, a 340, a 383, and a 440. They used stock replacement parts, stock cams and rocker gear, stock exhaust, and NO blueprinting, as regular production engines surely weren't. In all 3 cases, factory rated HP was very close. Small changes made to them after made some big power increases. All were well under carbed from the factory. The bigger carb, cam, and headers really seem to have woken up your dads 340.