Fits 90~95 ZR-1 LT5. NEW (NOS OEM water pump.  Comes Complete with  #10168678 NOS Water Pump Gasket included.

There are presently 2 different Delco part numbers in the Delco system. The "old" Delco #251-561 is phased out by "new" Delco #252-703. Same pump, different supplier to Delco. GM #10159599 is the Delco unit with casting #10135833. It has also appeared with GM #10135875 on the Delco box label, same casting number, brand new. Bottom line: There is no difference in pumps for any these part numbers.

Re-manufactured pumps were never offered by Delco or GM.