Well, unfortunately to add more to the confusion here, since there are multiple variables, let me give the following scenario.

Given two engines of equal displacement (say .28ci) and the same racing tricks thrown into them, they could both have different bores and strokes and make a difference on how they perform.

The .28ci engine with the smaller bore and longer stroke will produce more torque throughout the RPM range. This engine will not necessarily rev as high as an engine with a shorter stroke, primarily becaus of what ttoks already mentioned: materials science (the parts would excced their stress failure points and would break). Another factor con consider, given a conrod length, is piston linear speed (how fast the piston moves up and down in the cylinder). A longer stroke engine will have a much faster piston linear speed than an engine with a shorter stroke. This leads to friction and could also lead to a significant amount of heat from that friction (this is in addition to the materials sceience and inertial problems). This type of engine would be better for shorter tracks with shorter back straights since acceleration is what is needed.

The .28ci engine with the larger bore but smaller stroke will produce less torque than the engine above, but its primary advantage is that it can rev much higher before the problems of materials science will come into play. This type of engine is more suited to a lighter vehicle (in general) than the engine above would be put into. This engine is also better suited for tracks with longer back runs at the track (of course, gearing can be used to compensate).