My , the 470 combo is a better bang for the buck overall compared to the 4.15 crank 493-496; With the right compression, head and cam combo it can make near equal power so long as you have the valvetrain to carry the additional 400-500 rpm. For lighter A bodies the 470 9or even the 451) can even be an advantage in terms of tractible power to the ground in the more tire limited nose heavy combo. Theres NOTHING wrong with a 493 at all, it's just for my $$$ I'd build the 470 or.....

For a heavier B or E body car with mid 3 to low 4 gears where you really want the highest average streetable torque over the widest powerband possible the 4.25" crank 511 is the best overall motor to build.....in all practical terms you really can't throw too much head at these monsters.