Is there a difference in the water pump flange bolt pattern from a 1968 big block water pump to a 1969 big block water pump? I have a GM clutch fan that I took off a 69 big block and a guy is wanting to buy it to go a 1968 427 in his Camaro. I know his 68 has the short style water pump. I don't want to sell him something that will not fit. Any help would be appreciated.