The pictures that you have posted are for mid to late 60's small block with the cast iron water pump...
The OP has the 70 and later small block with the aluminum water pump - the brackets are different.... They mount similarly, but the brackets are different... The triangular bracket for the 60's style alt bracket has the one extra bolt that goes into a hole in the cast iron pump that the aluminum pump doesn't have... The aluminum water pump uses the two long water pump bolts to attach to the engine...
