Balancing helps make the rotating assembly stronger along with taking stress away from the block because it removes vibration that creates stress on bearings and the block and crank. The shop will wiegh the pistons, and match wieght them to the lightest piston and they will also do that with the connecting rods. Then they weight the rod bearings and the piston rings for one rod and piston and add these numbers to the wieght of the piston and connecting rod. They will then place a mocked up "bob) weight on each crank journal to mimic the eight rods and pistons. It will be placed in a balencing machine with the flywheel and harmonic balancer in place and spun up. The shop will then remove or add weight to the crank shaft as needed to smooth out and aliviate vibrations from the rotating assembly. This not only adds strenght but it makes HP because there is less HP loss on a smooth running assembly.

Stroke = the amount the crank moves the piston from the top of the cylinder to the bottom. The more stroke you have the more cubes you get.

Bore is the diameter of the cylinder in the engine. As you increase the diameter you increase the cubes also. There is also a slight bennefit to opening up the bore of a cylinder. You get the valves in the cylinder head farther away from the cylinder walls with a larger bore and this helps unshroud the valves allowing the engine to breathe better. This is more realistic to larger valve heads like a 2.02 inch intake or larger valve.

Another thing to take into consideration when adding stroke to a motor is rod ratio. A low rod ratio adds friction and piston side loading on the cylinder wall creating HP and torque loss along with placing more stress on the block.

The rod ratio of a 302 is 1.685
327/331 is 1.660
342/347 is 1.588
351 Cleveland is 1.653
351 Windsor is a high 1.701
A higher rod ratio is a bennefit to torque/HP and engine life.
Hope this helps.

 

Thats for the whole block assembly right? Do i need to buy that or can i buy just the pistons, rods, crank, new journal , and whatever else? That will prob be cheaper wont it? thanks guys, and sorry for hijacking the thread im just really curious