[lazysmurff]

bore something: larger displacement normally. boring out the cylinders of an engine leads to larger displacement, hence, more power. just dont go too big.

stroke increase: not too sure on this myself, but it has to do with lengthening the stroke of the pistons in the cylinders to create (again) more displacement, and more power.

Port and polish: refered to when speaking of heads mostly, which means basically to smooth out the valves, and then match the openings of the valves to their respective manifold perfectly.

new cams: usually going for bigger cams here. this causes the valves to be open longer and wider allowing more fuel to enter and exit the engine, thus more power.

pulleys: again, something else im not to sure about, but it has to do with replacing the big heavy pulleys with smaller lighter ones to decrease rotation mass that engine is spinning and thus sucking power away from your wheels, all without compromising the integrity of the systems being run.

hope that helps