Most spark plugs come pre-gapped, though you should always check the gap. Any Discount auto parts ussualy sells those little round disks that you use to gap plugs, which will work fine for checking the gap, to open it up, make sure you use the hole in the disc, and not something else, because you don't want to pry it open using leverage on the diode, otherwise, you may cause it damage, or worse to come off while it's in your motor. To close the gap on a plug, just tap it lightly against a hard flat surface. I really don't remember what stock gap is since I don't run it any more, but I think it's right around 42.

If you want to be more exact about your measurements, you can buy a feeler gauge set, but for most applications, and most people, that would be a little over kill, although if you adjust your own valves, you probably have it any way.

Installing them, I ussualy tighten snugly, and then just give them a little push more, and that ussualy does it, I think the torque spec is like 26 foot lbs, but i'm not really sure, you may want to double check. As I said, just by hand, and make sure it's tight, not a big deal.

Later!

Aj