The vanes on the old water pump impeller are curved. The new impeller vanes appear to be straight from pictures I have seen on the internet. Has the design of this impeller been changed, or do I bend the vanes to fit in the housing? If they do need to be bent which direction should I bend them. I am also having a hard time finding a gasket kit for this water pump. Part # on impeller 47-19453, new part # 18-8900. Thanks for any information.