Greetings. Did the 64's use an additional spacer between the pump and timing cover with a hole in it for the exposed impeller? I read this in a book but my car does not have it. I may be getting cavatation. This is not to be confused with the backplate that comes with the cast iron pumps. Thanks, Regis

 

Hey there. me again. If this is the wrong forum for my question, let me know and I'll move it. Thanks

 

No, Regis. You have come to the right place. Which engine do you have? Is it a 260 or a 289?

 

mine had what looked like a steel shim between the water pump and the housing. I'm not sure why it was there, but there is also a little notch on the timing cover at the bottom of the sealing surface that appears to act as a drain. I'm assuming that without that shim there, the pullies won't line up correctly.

 

It's a 289. It has the aluminum non-hipo pump and the appropriate timing cover for the pump. My question comes from what i read in the small block rebuild book. He states that a steel spacer is used and the impellor sticks through a hole in the plate. Most other people i talk to say there was/is no spacer plate. Again, This is not to be confused with the cast iron pumps that have a backplate. Thanks

 

The reason for a spacer would be to align the water pump pulley up with the belt. If it aligns without it, then don't use one. But if it doesn't, and needs a little more length to reach the perfect alignment with the belt, then it does.