Water pump question

[sheetmetaldan]

I was looking to get a water pump at rockauto. They have one pump with a 6 impeller blade and another with an 8 impeller blade. Whats the difference? I don`t know which one I have now but I don`t think it makes a difference I assume either will work. The price for the 8 blade is cheaper than the 6 blade.Does the 8 move more water and have better cooling capability? Small block 318 no A/C

 

[burntorange70]

Yep more flow with the 8 blade. 6 blade moves around 75 gpm and the 8 does 82. 6 blade was the standered pump used and the 8 was put in to AC cars. It is a good thing to check what you have but I would think it is a 6.

The 8 will also take a little more HP to turn it but I am not sure how much more.

You could also get the 8 and slow it down some with an undersize pully.

 

[Chryco Psycho]

it is substantial loss of hp 12-15 was what I recall seeing somewhere

 

[burntorange70]

Thats a lot more than I thought it would be but then them drag guys don't cut down the blades for nothing. LOL