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                                                                   EXHIBIT 10(w)

                             SEVENTH AMENDMENT TO
                  THIRD AMENDED AND RESTATED CREDIT AGREEMENT

     THIS SEVENTH AMENDMENT TO THIRD AMENDED AND RESTATED CREDIT AGREEMENT (this
"Amendment") dated as of the 20th day of March, 1998, by and among PLAINS
RESOURCES INC., a Delaware corporation (the "Company"), ING (U.S.) CAPITAL
CORPORATION, f/k/a Internationale Nederlanden (U.S.) Capital Corporation, as
Agent ("Agent"), and the Lenders under the Original Agreement (as defined
herein).

                                 W I T N E S S E T H:

     WHEREAS, the Company, Agent and Lenders entered into that certain Third
Amended and Restated Credit Agreement dated as of April 11, 1996, as amended by
that certain First Amendment to Third Amended and Restated Credit Agreement
dated December 16, 1996, that certain Second Amendment to Third Amended and
Restated Credit Agreement dated March 7, 1997, that certain Third Amendment to
Third Amended and Restated Credit Agreement dated July 18, 1997, that certain
Fourth Amendment to Third Amended and Restated Credit Agreement dated August 29,
1997, that certain Fifth Amendment to Third Amended and Restated Credit
Agreement dated November 3, 1997 and that certain Sixth Amendment to Third
Amended and Restated Credit Agreement dated February 10, 1998 (as amended, the
"Original Agreement") for the purposes and consideration therein expressed,
pursuant to which Lenders became obligated to make and made loans to the Company
as therein provided; and

     WHEREAS, the Company, Agent and Lenders desire to amend the Original
Agreement for the purposes described herein;

     NOW, THEREFORE, in consideration of the premises and the mutual covenants
and agreements contained herein and in the Original Agreement, in consideration
of the loans which may hereafter be made by Lenders to the Company, and for
other good and valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, the parties hereto do hereby agree as follows:

                   ARTICLE I. -- Definitions and References

     (S) 1.1.  Terms Defined in the Original Agreement.  Unless the context
otherwise requires or unless otherwise expressly defined herein, the terms
defined in the Original Agreement shall have the same meanings whenever used in
this Amendment.

     (S) 1.2.  Other Defined Terms.  Unless the context otherwise requires, the
following terms when used in this Amendment shall have the meanings assigned to
them in this (S) 1.2.

          "Amendment" means this Seventh Amendment to Third Amended and Restated
     Credit Agreement.

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          "Amendment Documents" means this Amendment.

          "Credit Agreement" means the Original Agreement as amended hereby.

                           ARTICLE II. -- Amendments

     (S) 2.1.   Use of Proceeds.  The last sentence of Section 8.17 of the
Original Agreement (which was added pursuant to the Sixth Amendment to the
Credit Agreement) is hereby amended to read as follows:

     In addition, the Company may use up to $55,000,000 of the proceeds of the
     Loans hereunder to make capital contributions to Unrestricted Subsidiaries
     as permitted in Section 8.10(e).

     (S) 2.2.  Investments.  Sections 8.10(e) and (f)  of the Original Agreement
(which were added pursuant to the Sixth Amendment to the Credit Agreement) are
hereby amended to read as follows:

          (e) capital contributions to Unrestricted Subsidiaries from time to
     time in an aggregate amount not to exceed $55,000,000;

          (f) in addition to any capital contributions permitted in subsection
     (e) above, the following Investments in Unrestricted Subsidiaries:   (i)
     captial contributions of up to $85,000,000 of the proceeds of any
     preferred or common stock of the Company issued after January 1, 1998; and
     (ii) any Investment represented by, or required to comply with the
     obligations undertaken under, the Stock Purchase Agreement described in
     Section 8.35(c);

     (S) 2.3. Unrestricted Subsidiaries. Section 8.35 of the Original Agreement
(which was added pursuant to the Sixth Amendment to the Credit Agreement) is
hereby amended to read as follows:

          Section 8.35  Unrestricted Subsidiaries.  The Company has or may form
     a new subsidiary to be known as Plains All American Inc., a Delaware
     corporation (such  subsidiary, and each of its subsidiaries, whether now
     existing or hereafter formed or acquired, each an "Unrestricted
     Subsidiary"), which Unrestricted Subsidiaries shall be subject to the
     following:

     (a)  Subject to subsection (d) below, no Unrestricted Subsidiary shall be
          deemed to be a "Subsidiary" of the Company for purposes of this
          Agreement or any other Basic Document, and no Unrestricted Subsidiary
          shall be subject to or included within the scope of any provision
          herein or in any other Basic Document, including without limitation
          any representation, warranty, covenant or Event of Default  herein or
          in any other Basic Document, except as set forth in this Section 8.35.

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     (b)  Except as permitted under Section 8.10(e) and (f) or Section 8.35 (c),
          neither the Company nor any of its Subsidiaries shall Guarantee any
          Indebtedness or other obligation of, grant any Lien on any of its
          Property to secure any Indebtedness or other obligation of, make any
          Investment in, assume or grant an indemnity with respect to, or
          provide any other form of credit support to, any Unrestricted
          Subsidiary, and neither the Company nor any of its Subsidiaries shall
          enter into (i) any management contract or agreement with any
          Unrestricted Subsidiary, except upon the prior written consent of
          Majority Lenders, not to be unreasonably withheld, or (ii) any other
          contract or agreement with any Unrestricted Subsidiary, except in the
          course of ordinary business on terms no less favorable to the Company
          or such Subsidiary, as applicable, than could be obtained in a
          comparable arm's length transaction from an unaffiliated party.

     (c)  Notwithstanding anything to the contrary contained in this Agreement,
          the Company and Plains All American Inc. may (i) enter into that
          certain Stock Purchase Agreement substantially in the form of the
          draft Stock Purchase Agreement attached hereto as Exhibit A, with such
          additions or modifications as may be agreed to by the Company and
          Plains All American Inc., provided that such additions or
          modifications shall not modify or increase any direct or indirect
          liability of the Company or any of its Subsidiaries (other than the
          liability of any Unrestricted Subsidiary) which arises or may arise
          under the Stock Purchase Agreement, unless such additions or
          modifications have been consented to by Majority Lenders, and (ii)
          observe and perform their respective obligations under the Stock
          Purchase Agreement, including, without limitation,  the consummation
          of the stock purchases contemplated thereby, but only insofar as any
          such observance or performance does not constitute or result in a
          default or violation of any Indenture or other agreement governing
          Indebtedness of the Company or its Subsidiaries.

     (d)  In the event Unrestricted Subsidiaries shall fail to consummate the
          transactions contemplated by such Stock Purchase Agreement prior to
          September 30, 1998, then on and after October 1, 1998 each
          Unrestricted Subsidiary shall be deemed to be a "Subsidiary" of the
          Company for purposes of this Agreement and shall be subject to the
          terms and conditions hereof.

                  ARTICLE III. -- Conditions of Effectiveness

     (S) 3.1.  Effective Date.  This Amendment shall become effective as of the
date first above written when and only when Agent shall have received, at
Agent's office, a counterpart of this Amendment executed and delivered by the
Company and Majority Lenders.

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                 ARTICLE IV. -- Representations and Warranties

     (S) 4.1. Representations and Warranties of the Company. In order to induce
Agent and Lenders to enter into this Amendment, the Company represents and
warrants to Agent and Lenders that:

          (a) The representations and warranties contained in Section 7 of the
     Original Agreement, are true and correct at and as of the time of the
     effectiveness hereof, subject to the amendment of certain of the Schedules
     to the Credit Agreement as attached hereto.

          (b) The Company and the Subsidiaries are duly authorized to execute
     and deliver this Amendment and the other Amendment Documents to the extent
     a party thereto, and the Company is and will continue to be duly authorized
     to borrow and perform its obligations under the Credit Agreement.  The
     Company and the Subsidiaries have duly taken all corporate action necessary
     to authorize the execution and delivery of this Amendment and the other
     Amendment Documents, to the extent a party thereto, and to authorize the
     performance of their respective obligations thereunder.

          (c) The execution and delivery by the Company and the Subsidiaries of
     this Amendment and the other Amendment Documents, to the extent a party
     thereto, the performance by the Company and the Subsidiaries of their
     respective obligations hereunder and thereunder, and the consummation of
     the transactions contemplated hereby and thereby, do not and will not
     conflict with any provision of law, statute, rule or regulation or of the
     certificate or articles of incorporation and bylaws of the Company or any
     Subsidiary, or of any material agreement, judgment, license, order or
     permit applicable to or binding upon the Company or any Subsidiary, or
     result in the creation of any lien, charge or encumbrance upon any assets
     or properties of the Company or any Subsidiary, except in favor of Agent
     for the benefit of Lenders.  Except for those which have been duly
     obtained, no consent, approval, authorization or order of any court or
     governmental authority or third party is required in connection with the
     execution and delivery by the Company or any Subsidiary of this Amendment
     or any other Amendment Document, to the extent a party thereto, or to
     consummate the transactions contemplated hereby and thereby.

          (d) When this Amendment and the other Amendment Documents have been
     duly executed and delivered, each of the Basic Documents, as amended by
     this Amendment and the other Amendment Documents, will be a legal and
     binding instrument and agreement of the Company and the Subsidiaries, to
     the extent a party thereto, enforceable in accordance with its terms,
     (subject, as to enforcement of remedies, to applicable bankruptcy,
     insolvency and similar laws applicable to creditors' rights generally and
     to general principles of equity).

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                          ARTICLE V. -- Miscellaneous

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     (S) 5.1.  Ratification of Agreements.  The Original Agreement, as hereby
amended, is hereby ratified and confirmed in all respects.  The Basic Documents,
as they may be amended or affected by this Amendment and/or the other Amendment
Documents, are hereby ratified and confirmed in all respects.  Any reference to
the Credit Agreement in any Basic Document shall be deemed to refer to this
Amendment also.  The execution, delivery and effectiveness of this Amendment and
the other Amendment Documents shall not, except as expressly provided herein or
therein, operate as a waiver of any right, power or remedy of Agent or any
Lender under the Credit Agreement or any other Basic Document nor constitute a
waiver of any provision of the Credit Agreement or any other Basic Document.

     (S) 5.2. Ratification of Security Documents. The Company, Agent and Lenders
each acknowledge and agree that any and all indebtedness, liabilities or
obligations arising under or in connection with the Notes are Obligations and is
secured indebtedness under, and is secured by, each and every Security Document
to which the Company is a party. The Company hereby re-pledges, re-grants and 
re-assigns a security interest in and lien on every asset of the Company
described as collateral in any Security Document.

     (S) 5.3. Survival of Agreements. All representations, warranties, covenants
and agreements of the Company herein and in the other Amendment Documents shall
survive the execution and delivery of this Amendment and the other Amendment
Documents and the performance hereof and thereof, including without limitation
the making or granting of each Loan, and shall further survive until all of the
Obligations are paid in full. All statements and agreements contained in any
certificate or instrument delivered by the Company or any Subsidiary hereunder,
under the other Amendment Documents or under the Credit Agreement to Agent or
any Lender shall be deemed to constitute representations and warranties by, or
agreements and covenants of, the Company under this Amendment and under the
Credit Agreement.

     (S) 5.4.  Basic Documents.  This Amendment and each of the other Amendment
Documents is a Basic Document, and all provisions in the Credit Agreement
pertaining to Basic Documents apply hereto and thereto.

     (S) 5.5.  GOVERNING LAW.  THIS AMENDMENT AND THE OTHER AMENDMENT DOCUMENTS
SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF
NEW YORK AND ANY APPLICABLE LAWS OF THE UNITED STATES OF AMERICA IN ALL
RESPECTS, INCLUDING CONSTRUCTION, VALIDITY AND PERFORMANCE.

     (S) 5.6.  Counterparts.  This Amendment and each of the other Amendment
Documents may be separately executed in counterparts and by the different
parties hereto in separate counterparts, each of which when so executed shall be
deemed to constitute one and the same Amendment or Amendment Document, as the
case may be.

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     IN WITNESS WHEREOF, this Amendment is executed as of the date first above
written.

                              PLAINS RESOURCES INC.

                              By: /s/  PHILLIP D. KRAMER
                                 ------------------------------------------
                                 Phillip D. Kramer
                                 Vice President and Chief Financial Officer


                              ING (U.S.) CAPITAL CORPORATION,
                              f/k/a Internationale Nederlanden (U.S.) Capital
                              Corporation, individually as a Lender and as
                              Agent

                              By: /s/  CHRISTOPHER R. WAGNER
                                 ------------------------------------------
                                 Christopher R. Wagner, Vice President


                              BANKBOSTON, N.A., Lender

                              By: /s/   TERRENCE RONAN
                                 ------------------------------------------
                                 Name:  Terrence Ronan
                                 Title:


                              WELLS FARGO BANK (TEXAS),
                              NATIONAL ASSOCIATION
                              (f/k/a First Interstate Bank of Texas, N.A.),
                              Lender

                              By: /s/  ANN M. RHOADS
                                 --------------------------------------------
                                 Ann M. Rhoads, Vice President

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                              CHASE BANK OF TEXAS, NATIONAL ASSOCIATION (f/k/a
                              Texas Commerce Bank National Association), Lender

                              By: /s/  RUSSELL A. JOHNSON
                                 ---------------------------------------------
                                 Name: Russell A. Johnson
                                 Title: Vice President


                              COMERICA BANK-TEXAS, Lender

                              By: /s/  JAMES KIMBLE
                                 ---------------------------------------------
                                 Name: James Kimble
                                 Title: Assistant Vice-President

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                                 CONSENT AND AGREEMENT
                                 ---------------------

     Each of the undersigned Subsidiary Guarantors hereby consents to the
provisions of this Amendment and the transactions contemplated herein and hereby
(i) acknowledges and agrees that any and all indebtedness, liabilities or
obligations arising under or in connection with the Notes are Obligations and
are secured indebtedness under, and are secured by, each and every Security
Document to which it is a party, (ii) re-pledges, re-grants and re-assigns a
security interest in and lien on all of its assets described as collateral in
any Security Document, (iii) ratifies and confirms its Amended and Restated
Guaranty dated April 11, 1996 made by it for the benefit of Agent and Lenders,
and (iv) expressly acknowledges and agrees that such Subsidiary Guarantor
guarantees all indebtedness, liabilities and obligations arising under or in
connection with the Notes pursuant to the terms of such Amended and Restated
Guaranty, and agrees that its obligations and covenants thereunder are
unimpaired hereby and shall remain in full force and effect.

                         PLAINS MARKETING & TRANSPORTATION INC.
                         PLAINS RESOURCES INTERNATIONAL INC.
                         PLAINS TERMINAL & TRANSFER CORPORATION
                         PLX CRUDE LINES INC.
                         STOCKER RESOURCES, INC.
                         PLX INGLESIDE INC.
                         CALUMET FLORIDA, INC.
                         PLAINS ILLINOIS INC.


                         By:/s/  PHILLIP D. KRAMER
                            -----------------------------------------------
                            Phillip D. Kramer
                            Vice President and Chief Financial Officer


                         STOCKER RESOURCES, L.P.

                         By:  Stocker Resources, Inc.,
                               its General Partner


                         By:/s/  PHILLIP D. KRAMER
                            -----------------------------------------------
                                 Phillip D. Kramer
                                 Vice President and Chief Financial Officer

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