[Goat4three]

first of all, i believe the only pump with the 4" hub is on the '69 engine, the rest are 4.5"....i believe.

as for measuring, if the water pump is off of the car, start the measurement at the machined surface on the impeller side of the housing where the gasket would go and measure to flange surface where the fan would mount. for ease of measurement, use a straight edge and line it up on the flange and measure back to the housing.

hope this helps.

[cejay825]

I didn't know they made a water pump like that. will pick one up. good info !

[Ratman]

I just tried to decrease the gap btwn the divider plates and the impeller this weekend. I was using a rubber mallet and got the clearence down to about .100. The car ran warmer than it was before I made the adjustment. My questions are: what kind of tool is everyone using to decrease the gap, and what should that gap ideally be. My next question, should the entire divider plate be manipulated down to meet the impeller, or just the inside edge. If anyone has pictures showing the ideal gap, I would appreciate it. I have been chasing this overheating problem for about 3 years, I have a stroker 400 pushing over 600 horses and connot afford to let it get hot. Please HELP!