what exactly is done?

whats done when your block is blue printed and internals balanced? what are the pro's to having this done and why is it so important if goin all motor with high hp engines. thanks

less strain on the motor if oveall mass is equal.You gain the power by balacing and shaving off a few grams on the crank, pistons and rods.if all the pistons and rods are equal in weight then the overall mass rotation will rotate alot smoother,same ass the crank,if thats balanced with the rods and pistons than everything rotates as one.Its all physics

bluprinting is a complety taring down your motor and measuring all parts and puting them to perfect spec. when motors are turned off the assembly line they arnt perfect they are built within serten tolerances wich gets you down the road and will last for along time but if your racing it you can narow thoes toleranced down. go to a machene shop