The bracket for the PS pump normally hangs off the water pump with a bracket mounted to the front of the left exhaust manifold for the adjustment. As far as I know the 70-76 should be close to the same. Not having mount holes in the heads is a puzzler since just about all small blocks had mount holes from about 67. The standard alt bracket for that model normally is located on the front of the right head and water pump and picks up one of the thermostat bolts for the top mount location.
Fred
