How do you rebuild a 1968 buick 430cu. engine to perform better than stock?

i want to give the machine shop im using for the rebuild some specs, and performance mods for a nice mild street motor. ive been told that Buick's are different than Chevy's, and most machinist are used to building chevy motors.|||Find a machine shop that deals with performance engines and they can recommend all the mods your budget will allow.