<PAGE>
 
       WHEREFORE, the parties have caused this Agreement to be executed by their
duly authorized officers as of the date first above written.

                                              ZAPATA CORPORATION


                                              By:  /s/ Lamar C. McIntyre
                                                 -----------------------------
                                              Name:  Lamar C. McIntyre
                                                   ---------------------------
                                              Title:  V.P. Treas. & CFO
                                                    --------------------------

                                              ZP ACQUISITION CORP.


                                              By:  /s/ Joseph D. Oliver
                                                 -----------------------------
                                                 Name: Joseph D. Oliver
                                                      ------------------------
                                                 Title: Vice President
                                                       -----------------------

       Codepa, Ltd. Financing Facility, a Massachusetts Business Trust, hereby
fully and unconditionally guarantees the performance by the Buyer of all
obligations, covenants and agreements of Buyer to be performed before or at the
Closing, pursuant to the terms of the Agreement set forth above.

                                             CODEPA, LTD. FINANCING FACILITY,
                                             a Massachusetts Business Trust


                                             By:
                                                ------------------------------
                                                Name:
                                                     -------------------------
                                                Title:  Trustee

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