Camshaft help.....340 Dart Swinger

For me....for street/strip performance, if it doesn't lift the valve an honest .500 or better...its the wrong camshaft.
Street performance near stock manners...I wouldn't be using a 284 duration anything unless it comes with .500 or better lift and its a 4 spd application Or 3.91 +gears.

On average its hard to give bad advice based on those guidelines.