Today, dollar for dollar, is the 318 faster than the 340 ???

Keep in mind.... my current '74 Duster.....
stone-stock 318 2bbl with dual exhaust. I put exactly 498 bucks into it including carb and gaskets, and ran high 14's at about 95 mph. Still stock converter and 2.76 gears. Again, under 500 and I ran what '73 340 Dusters ran and even more mph, with my 2.76 gears.