340 cam in a 318

Dan,
[1] Forget about DCR with a hyd cam. It changes as the lifters bleed down. See how many have used DCR to ' design' a cam that will not ping...& got pinking anyway.
[2] Sure, a 340 cam will give more top end power. But it could reduce low end power. The 318...being only 318 cubes.......is not over endowed with low end tq......unless you use nitrous, blower, etc. So the answer is choose wisely & decide beforehand what if anything you are willing to forego, such as idle quality etc.
[3] I would NOT use a factory a factory cam. They are usually dual pattern to work with a restrictive factory exh system. They also have wide LSA [ no good ] to comply with emission requirements, noise etc.
[4] The cam I would use that you should give the butt meter a real kick in the butt, & retain all of it's street manners, is the Isky 262 Supercam.