I agree with chunky. I also beg to differ on the thought that an engine is more reliable if you increase bore AND stroke. Less piston speed and a more favorable r/s ratio can be used to increase reliability, while a larger bore can be used to increase displacement and still keep pistons speeds down.chunky` said:Not to split hairs, but Increasing stroke results in higher intake air velocities v.s. a same displacement motor with less stroke but more bore. This is simply a result of the higher piston speeds at a given RPM. This is also why more stroke = less RPM potential b/c the piston speeds are higher for a given RPM.
there's a tradeoff for everything. More stroke = better low end power, but you can build a big bore motor that will rev higher and can thus use a shorter gear to produce essentially the same torque for a given vehicle speed.
You know this already though. You are destroking a motor and increasing the bore because it is more beneficial for higher RPM reliability to reduce piston speeds, while still maintaining a larger displacement.