1974 440. Cast crank. 2 harmonic balancers were included with the engine but neither was installed. Both are cast, both in great shape. The lower pulley i have is a 4 row pulley and I have AC, power brakes, power steering. Both have the same diameter. The 6 pulley bolts line up perfectly with the thinner (7/8") one. They are off a bit on the thicker one (1 5/8"), but will fit. Does it matter which one I use?