Verify the difference between a long vs a short connecting rod - lets assume bore is 4 and stroke is 3 -what efffect would it have horsepower torque?

long rod=more stroke and more torque The above is a common misconception. Stroke is determined by the "throw" of the crankshaft. The rod length only determines how high the piston travels into the cylinder. You'll need to match the rod to the piston so that the piston doesn't hit the cylinder head at the top of the stroke or the crankshaft at the bottom of the stroke. But think about it. The total stroke is not determined by the rod, but by by the difference between the crankshaft center at the top of the stroke versus the bottom.

EDIT: Can i see some mathematical formula (with trig) with the example if possible PLEASE !

Thanks guys