Sounds to me like you have the plugs in the wrong firing order. If you've got the motor together, you won't be able to see the timing marks. That's why I said to use the screwdriver method.

A friend of mine has snapped 2 timing belts, shaken hands with the valves, and re-used his rotating assembly after replacing his head. He's running 12's on about 24 PSI. Scratching your piston won't hurt it at all unless you bought ceramic coated pistons or something like that.

You'll have to pull your valve cover off in order to see the cam timing marks. You can skip the screwdriver method if you feel like doing that. Might as well pull it just to be sure. Line everything up, check your distributor and 1-3-4-2 clockwise from there.