THE GREAT THING ABOUT A CUSTOM BUILT ENGINE IS YOU CAN PUT EXACTLY THE PARTS YOU WANT IN IT.YOU CAN PICK AND CHOOSE FROM DIFFERENT BRAND NAMES.YOU CAN WORK WITH THE ENGINE BUILDER TO COME UP WITH THE RIGHT COMBO.ALSO REMEMBER EVERY PERSONS APPLICATION IS NOT THE SAME.YOU REALLY DO GET WHAT YOU PAY FOR.A CUSTOM BUILT ENGINE IS HELD TO MORE EXACTING TOLERANCE'S AND NOT A (COOKIE CUTTER )ENGINE.ANOTHER THING IS A GOOD ENGINE BUILDER ACTS AS A MACHINIST,AN ENGINEER AND A PARTS MAN AND A SALESMAN.