I think that if you will check the various models of the Delco blower motor you will find that for some vehicles they run clockwise and for others they run counter-clockwise e.g.. Buick vs Chevrolet. The discussion over modification isn't really necessary if you pick the right model. Having said this and put myself at risk of attack, I don't have the specific part numbers. I did replace mine several years ago & went through the same search for a solution. (Before I discovered that there were 2 genders of motor). Richard