datnut

I went ahead and ordered the big ATI, so I can compare sizes to see whether it overdrives, underdrives, or doesn't change the water pump.

Thanks for the help. I believe the two OE water pump pulleys have different part numbers, but I am now starting to think that the differences lie in the diameter of the pulleys and they may be different to compensate for a difference in the OE Crankshaft pulley diameters. If my assumptions are correct then I guess I would be fine using the ATI 1000HP pulley since its water pump pulley has the correct diameter to work with it. Again, thanks. Paul

I've exhausted my search options on this question, so I hope it has not already been posted elsewhere. I am trying to determine if I can use the larger 1000HP ATI damper on an RB25det. I realize that either of the dampers offered from ATI will fit the crank, but the 1000HP one includes a new water pump pulley and I have not been able to verify that the water pump pulley, designed for an RB26dett will work on the RB25det. As a fall back I will order the 600 HP damper, but I would prefer to order the larger one if the water pump pulleys are interchangeable. On a side not, if they are interchangeable, can you then use the Greddy light weight pulleys on an RB25det? Thanks in advance, Paul