Ok, ur engine is nothing more than a mildly better version of the new 1987 and up 350. 3.5 is a 6 cylinder ( I belive ) 5.0 is a Ford 302 or Chevy 305 and a 5.7 is a Chevy 350 and a 5.8 would be a Ford 351. Balancing is just balancing the rotating assembly so it is not off balance, this is done by a machine calculating stuff when crank and weights ( equivilant to the pistions and rods weight combined ) are rotated at a fair amount of speed, and the computer tells u what size hole and where to drill it in the crank shaft, which balances the engine. I'm unshure of Bluprinting.