With the water pump I bought, the difference was clearly the number of >impeller blades. The pulley is not part of the pump - it bolts on >separately. > >Ken Miller Even though the pulley does not come with the pump, a/c and non a/c cars may have different size pulleys. The belt path is obviously different. I was told on the MML that the a/c pumps have less impellers and a smaller pulley. Of course my discussion was about the small block ( I just did my '83). The big block is different and the pump is separate from the housing so I am not sure about them. Haven't done my 440 since before I got my license (1985) ROb _________________________________________________________________ Join the world’s largest e-mail service with MSN Hotmail. http://www.hotmail.com