Exhibit 5.1

                     [VALERO ENERGY CORPORATION LETTERHEAD]

                                 March 25, 2004

Valero Energy Corporation
One Valero Place
San Antonio, Texas 78212

Ladies and Gentlemen:

                  I am Vice President and Secretary of Valero Energy
Corporation, a Delaware corporation (the "Company"), and have acted as counsel
for the Company in connection with its offering of $200,000,000 aggregate
principal amount of 3.50% Notes due April 1, 2009 (the "2009 Notes") and
$200,000,000 aggregate principal amount of 4.75% Notes due April 1, 2014 (the
"2014 Notes" and, together with the 2009 Notes, the "Notes"), which it is
offering under the Registration Statement on Form S-3, as amended by Amendment
No. 1 thereto (Reg. Nos. 333-84820, 333-84820-01 and 333-84820-02) (the
"Registration Statement") filed by the Company and VEC Trust III and VEC Trust
IV, each a statutory trust formed under the laws of the State of Delaware (the
"Trusts"), with the Securities and Exchange Commission (the "Commission") under
the Securities Act of 1933, as amended (the "Securities Act"). The Registration
Statement relates to the proposed issuance and sale from time to time by the
Company and the Trusts of various securities under the Securities Act's Rule
415.

                  The Notes will be issued pursuant to an indenture dated as of
December 12, 1997 between the Company and The Bank of New York, as Trustee (the
"Senior Indenture").

                  In furnishing this opinion, I or members of my staff have
examined and relied without investigation as to matters of fact upon, copies of
the Restated Certificate of Incorporation and Restated By-laws of the Company,
as amended to date; the Senior Indenture; the Registration Statement and its
exhibits; the prospectus included in the Registration Statement; the prospectus
supplement dated March 22, 2004 and filed with the Commission on March 23, 2004
under the Securities Act's Rule 424(b)(5); the underwriting agreement, dated
March 22, 2004, among the Company and Lehman Brothers Inc., Barclays Capital
Inc., Morgan Stanley & Co. Incorporated, RBC Capital Markets Corporation, BNP
Paribas Securities Corp., Citigroup Global Markets Inc., Credit Lyonnais
Securities (USA) Inc., Mizuho International plc, Scotia Capital (USA) Inc. and
SunTrust Capital Markets, Inc., as underwriters, relating to the offering and
sale of the Notes (the "Underwriting Agreement"); the resolutions of the Board
of Directors of the Company (the "Board") and a special committee of the Board
which authorize the issuance of the Notes and approve the terms of the offering
and sale of the Notes (collectively, the "Board Action"); corporate records of
the Company, including minute books of the Company; certificates of public
officials and of representatives of the Company; statutes and other instruments
and documents as I have deemed necessary or appropriate to form a basis for the
opinions hereinafter expressed.



Valero Energy Corporation
March 25, 2004
Page 2

                  In connection with this opinion, I have assumed: (a) the
genuineness of all signatures on all documents examined by me and (b) the
authenticity of all documents submitted to me as originals and the conformity to
the originals of all documents submitted to me as copies.

                  On the basis of the foregoing, and subject to the assumptions,
limitations and qualifications set forth herein, I am of the opinion that:

         1.       The Company is a corporation duly organized and validly
existing in good standing under the laws of the State of Delaware.

         2.       The Notes, when they have been duly executed, authenticated,
issued and delivered in accordance with the Senior Indenture and the Board
Action, and duly purchased and paid for in accordance with the provisions of the
Underwriting Agreement, will constitute legal, valid and binding obligations of
the Company, enforceable against the Company in accordance with their terms,
except as the enforceability thereof is subject to the effect of (i) bankruptcy,
insolvency, reorganization, moratorium, fraudulent conveyance or other laws
relating to or affecting creditors' rights generally and (ii) general principles
of equity (regardless of whether such enforceability is considered in a
proceeding in equity or at law).

                  The opinions set forth above are limited in all respects to
matters of Texas law, the General Corporation Law of the State of Delaware and
the federal laws of the United States, in each instance as currently in effect,
and in each case, exclusive of municipal, local and county ordinances, laws,
rules and regulations. At your request, this opinion is being furnished to you
for filing as Exhibit 5.1 to Valero's current report on Form 8-K reporting the
offering of the Notes. Additionally, I hereby consent to the reference to me
under the caption "Legal Matters" in the Registration Statement. In giving such
consent, I do not thereby concede that I am within the category of persons whose
consent is required under Section 7 of the Securities Act or the rules and
regulations of the Commission promulgated thereunder.

                                           Very truly yours,

                                           /s/ Jay D. Browning