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You may need to swap your existing alternator bracket to a 385-series bracket.

Also, the small block coolant surge tank won't work on a 385. On a small block, the water exits the intake manifold horizontally. On a 385, the water exits the intake manifold vertically. You'll either have to fashion a custom 90 degree elbow, or come up with another way to vent the air out of the radiator. My car uses a 1970s Corvette surge tank.