what is meant by "a stroked engine?" is just making the lenght of the rod longer? would they not need a taller jug? thanks

 

A basic explanation:

Stroking an engine means increasing the distance that the piston travels on the vertical. This combined with the size of the piston give us the volume that an engine displaces as the piston moves up and down. Bore area x stroke = displacement. To get the rod to move the piston more, the crank needs to be modified to put the bottom rod pin farther from the center of the crankshaft. The farther you put it out, the farther the rod will move up and down.

Just getting a longer rod will not increase displacement because the rod is just moving the same distance at a different point relative to the crankshaft. All that will happen is you will probably smash your piston into your valves, minimal performance gain even without that.

If you use a stock length rod for a stroker you will probably need a special piston or a cylinder spacer. Some builders use a shorter rod to use stock spec pistons and stock cylinder w/o a spacer. Many dont like the spacer because it is a dead giveaway that the motor is stroked.

 

Translation, think of a syringe, if you pull the stopper out farther it sucks more stuff in. Putting a longer stopper in it wont help if you dont add more travel, you just have a longer handle.