SC 13D/A

CUSIP NO. 726540503

SCHEDULE 13D

(Rule 13d-101)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO RULE 13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO

RULE 13d-2(a)

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Under the Securities Exchange Act of 1934*

(Amendment No. 6)

Plains Resources Inc.

(Name of Issuer)

Common Stock, par value $0.10 per share

(Title of Class of Securities)

726540503

(CUSIP Number)

Paul G. Allen

Vulcan Energy Corporation

505 Fifth Avenue S, Suite 900

Seattle, Washington 98104

(206) 342-2000

James C. Flores

Plains Resources Inc.

700 Milam, Suite 3100

Houston, Texas 77002

(832) 239-6000

John T. Raymond

Plains Resources Inc.

700 Milam, Suite 3100

Houston, Texas 77002

(832) 239-6000

(Name, Address and Telephone Number of Person(s) Authorized to Receive Notices and Communications)

July 20, 2004

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box  ¨.

Note.  Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Continued on following page(s)

CUSIP NO. 726540503

1	NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON             Vulcan Energy Corporation
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨ (b)  x
3	SEC USE ONLY
4	SOURCE OF FUNDS*             N/A
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)	¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION             Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH   7    SOLE VOTING POWER:                 0 shares (1)   8    SHARED VOTING POWER:                 2,839,519 shares (1)(2)   9    SOLE DISPOSITIVE POWER:                 0 shares (1) 10    SHARED DISPOSITIVE POWER:                 0 shares (1)

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON             0 shares (2)
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*	x
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)             0%
14	TYPE OF REPORTING PERSON*             CO

⁽¹⁾ Vulcan Energy Corporation and Paul G. Allen have entered into an Amended and Restated Subscription Agreement with James C. Flores and John T. Raymond (please see Item 6) and may be deemed members of a “group” with respect to the shares of Issuer owned by Messrs. Flores and Raymond. Vulcan Energy Corporation and Paul G. Allen disclaim membership in a group with, and beneficial ownership of the shares of Issuer owned by, Messrs. Flores and Raymond.

⁽²⁾ Vulcan Energy Corporation has entered into a Voting Agreement with Kayne Anderson Capital Advisors, L.P. (“KACA”) and EnCap Investments, LLC (“EnCap”) (please see Item 6) and may be deemed a member of a “group” with respect to the shares of Issuer owned by KACA and EnCap. Paul G. Allen is the sole shareholder of Vulcan Energy Corporation. Vulcan Energy Corporation and Mr. Allen disclaim membership in a group with, and beneficial ownership of, the shares of Issuer owned by KACA and EnCap.

*SEE INSTRUCTIONS BEFORE FILLING OUT!

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CUSIP NO. 726540503

1	NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON             Paul G. Allen
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨ (b)  x
3	SEC USE ONLY
4	SOURCE OF FUNDS*             N/A
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)	¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION             United States

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH   7    SOLE VOTING POWER:                 0 shares (1)   8    SHARED VOTING POWER:                 2,839,519 shares (1)(2)   9    SOLE DISPOSITIVE POWER:                 0 shares (1) 10    SHARED DISPOSITIVE POWER:                 0 shares (1)

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON             0 shares (2)
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*	x
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)             0%
14	TYPE OF REPORTING PERSON*             IN

⁽¹⁾ Vulcan Energy Corporation and Paul G. Allen have entered into an Amended and Restated Subscription Agreement with James C. Flores and John T. Raymond (please see Item 6) and may be deemed members of a “group” with respect to the shares of Issuer owned by Messrs. Flores and Raymond. Vulcan Energy Corporation and Paul G. Allen disclaim membership in a group with Messrs. Flores and Raymond.

⁽²⁾ Vulcan Energy Corporation has entered into a Voting Agreement with Kayne Anderson Capital Advisors, L.P. (“KACA”) and EnCap Investments, LLC (“EnCap”) (please see Item 6) and may be deemed a member of a “group” with respect to the shares of Issuer owned by KACA and EnCap. Paul G. Allen is the sole shareholder of Vulcan Energy Corporation. Vulcan Energy Corporation and Mr. Allen disclaim membership in a group with, and beneficial ownership of, the shares of Issuer owned by KACA and EnCap.

*SEE INSTRUCTIONS BEFORE FILLING OUT!

3

CUSIP NO. 726540503

1	NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON             James C. Flores
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  x (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS*             N/A
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)	¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION             United States

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH   7    SOLE VOTING POWER:                 1,226,428 shares   8    SHARED VOTING POWER:                 0 shares   9    SOLE DISPOSITIVE POWER:                 1,226,428 shares 10    SHARED DISPOSITIVE POWER:                 0 shares

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON             1,226,428 shares
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*	¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)             5.00%
14	TYPE OF REPORTING PERSON*             IN

*SEE INSTRUCTIONS BEFORE FILLING OUT!

4

CUSIP NO. 726540503

1	NAMES OF REPORTING PERSONS S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON             John T. Raymond
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨ (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS*             N/A
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)	¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION             United States

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH   7    SOLE VOTING POWER:                 421,223 shares   8    SHARED VOTING POWER:                 0 shares   9    SOLE DISPOSITIVE POWER:                 421,223 shares 10    SHARED DISPOSITIVE POWER:                 0 shares

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON             421,223 shares
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*	¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)             1.72%
14	TYPE OF REPORTING PERSON*             IN

*SEE INSTRUCTIONS BEFORE FILLING OUT!

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CUSIP NO. 726540503

This sixth amendment to the Schedule 13D amends the Schedule 13D originally filed with the Securities and Exchange Commission (the “SEC”) on December 1, 2003, as amended on February 26, 2004, as amended on March 25, 2004, as amended on April 15, 2004, as amended on July 13, 2004 and as amended on July 19, 2004. Capitalized terms not otherwise defined herein shall have the meaning ascribed thereto in the Schedule 13D.

Item 4. Purpose of Transaction

The following is hereby added to Item 4:

On July 20, 2004, Vulcan sent a letter to the Issuer’s board of directors attaching a model illustrating the likely achievable value in a leveraged recapitalization using reasonable assumptions discussed with the board of directors and detailed in Vulcan’s letter sent to the board of directors on July 19, 2004 (attached to Amendment No. 5 to this Schedule 13D). A copy of the letter delivered to the board of directors is attached hereto as Exhibit 99(a) and is incorporated by reference herein.

Item 7. Material to be Filed as Exhibits

99(a)	Letter from Vulcan Energy Corporation to the Board of Directors of Plains Resources, Inc., dated July 20, 2004.
99(b)	Joint Filing Agreement (incorporated by reference to Exhibit 99(b) of the Schedule 13D filed jointly by Vulcan Energy Corporation, Paul G. Allen, James C. Flores and John T. Raymond on December 1, 2003).

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SIGNATURES

After reasonable inquiry and to the best of its knowledge and belief, the undersigned certifies that the information set forth in this Statement is true, complete and correct.

Date: July 20, 2004

VULCAN ENERGY CORPORATION
By:	/s/ David Capobianco
Name:	David Capobianco
Title:	Vice President

SIGNATURES

After reasonable inquiry and to the best of his knowledge and belief, the undersigned certifies that the information set forth in this Statement is true, complete and correct.

Date: July 20, 2004

/s/ Paul G. Allen

Paul G. Allen

SIGNATURES

After reasonable inquiry and to the best of his knowledge and belief, the undersigned certifies that the information set forth in this Statement is true, complete and correct.

Date: July 20, 2004

/s/ James C. Flores

James C. Flores

SIGNATURES

After reasonable inquiry and to the best of his knowledge and belief, the undersigned certifies that the information set forth in this Statement is true, complete and correct.

Date: July 20, 2004

/s/ John T. Raymond

John T. Raymond

Exhibit Index

Name of Exhibit
99	(a)	Letter from Vulcan Energy Corporation to the Board of Directors of Plains Resources, Inc., dated July 20, 2004.
99	(b)	Joint Filing Agreement (incorporated by reference to Exhibit 99(b) of the Schedule 13D filed jointly by Vulcan Energy Corporation, Paul G. Allen, James C. Flores and John T. Raymond on December 1, 2003).

EX-99.(A)

Exhibit 99(a)

VULCAN ENERGY CORPORATION

505 FIFTH AVENUE SOUTH

SEATTLE, WASHINGTON 98104

July 20, 2004

Via Facsimile (832) 239-6210

Plains Resources Inc.

700 Milam Street, Suite 3100

Houston, Texas 77002

Attn: Board of Directors

Gentlemen:

Further to our letter we sent you on July 19, 2004, attached for your information is a model illustrating the value that is likely to be achievable in a leveraged recapitalization. In our model, we use reasonable assumptions that we have discussed with you and detailed in our July 19th letter and that you have further clarified in your July 19th press release. As we have also discussed, we arrive at an implied share price for the post-recapitalized Plains Resources of $12.07 - $14.13 per share. In addition, we have provided a net asset value analysis which clearly shows that the net asset value per share, after giving effect to a $7.95 to $8.35 per share embedded tax liability, is $11.46 to $12.05.

We remain committed to completing our $17.25 per share all-cash transaction with Plains Resources.

Respectfully,

/s/ David N. Capobianco

David N. Capobianco

Vice President

Attachment

cc: R. Joel Swanson, Baker Botts L.L.P.

Plains Resources Inc.

Recapitalization Analysis assuming Tender @ $18.00 per share

	PLX Pro forma Recapitalization Value
	Midpoint (a)			High end (b)
PAA 2005E LP Distribution	$	2.44		$	2.58
PAA LP units		12.4			12.4
LP unit cash flow		30.3			32.0
PAA General Partner cash flow (c)		6.5			7.9
Total Cash Flow	$	36.7		$	39.8
Less: G&A		(2.5	)		(2.5	)
EBIT	$	34.2		$	37.3
Interest expense @ 7.5% rate		(11.3	)		(11.3	)
Pre-tax income	$	23.0		$	26.1
Taxes @ 20% rate		(4.6	)		(5.2	)
Free Cash Flow	$	18.4		$	20.9
Free Cash Flow Multiple		12.5x			12.5x
PLX Equity capitalization	$	230.0		$	261.0
Pro forma average 2005 fully-diluted shares		19.1			19.0
PLX post-Recap share price	$	12.07		$	13.75

	PLX pro forma share price sensitivity
Tender Price
$17.00	$	12.40	$	14.13
$18.00	$	12.07	$	13.75

Summary Recapitalization Assumptions

Tender Price per share	$	18.00
New Debt raised	$	150.0
Calumet sale proceeds		20.0
Total Sources of Cash	$	170.0
Repayment of Net debt		(28.1	)
Fees and Expenses		(38.0	)
Cash available for Tender	$	103.9

(a) Plains All American LP distribution as per PLX Board of Directors, July 19th, 2004 press release.

(b) Plains All American LP distribution based on high end of guidance, as per PAA press release dated June 16th, 2004.

(c) Plains All American LP units outstanding as per PAA 8-K dated June 16th, 2004.

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Plains Resources Inc.

Recapitalization Analysis assuming Tender @ $18.00 per share

Cash Sources and Uses—Comparison to LUK Model

LUK Assumptions

New Debt issued	$	175.0
Calumet sale proceeds		35.0
LUK Sources	$	210.0
Repayment of Net debt		(10.0	)
Transaction / Financing fees		(5.0	)
Management Severance		(5.0	)
Vulcan Capital Expenses		(6.0	)
LUK Cash Available for Tender	$	184.0

Adjustments for Inaccurate Assumptions

Less: Incremental debt over reasonable leverage ($150MM)		(25.0	)
Less: Net debt understatement		(18.1	)
Less: Calumet sale proceeds overstatement		(15.0	)
Less: Vulcan break-up fee (a)		(15.0	)
Less: PLX transaction-related expenses (a)		(5.0	)
Less: 280G tax gross-up payment related to severance		(2.0	)
Cash Available for Tender	$	103.9
LUK Overstatement of Cash Available for Tender	$	80.1
Net Debt Calculation (b)
Short-term Debt	$	20.0
Long-term Debt		25.0
Funded working capital (c)		4.0
Cash		(15.8	)
Restricted cash		(5.1	)
Net Debt	$	28.1

(a) Based on PLX proxy statement dated June 23rd, 2004.

(b) PLX public filings.

(c) Estimate based upon PLX working capital needs.

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PLX Net Asset Value

PLX Net Asset Value
($ in millions)
	Low			High
Price of PAA LP Unit	$	35.40		$	35.40
Number of PAA LP Units		12.4			12.4
LP Unit Valuation	$	439.0		$	439.0
GP Valuation		70.0			90.0
Calumet Florida Oil & Gas Valuation		20.0			25.0
Pre-Tax Enterprise Value (LP+GP+Florida)	$	529.0		$	554.0
Tax Liability @ 40.0%		(200.7	)		(210.7	)
Net Asset Value	$	328.3		$	343.3
Net Debt		(28.1	)		(28.1	)
Fees and Expenses		(11.0	)		(11.0	)
Equity Value	$	289.2		$	304.2
Fully Diluted Shares Outstanding		25.2			25.2
Net Asset Value After Tax ($ / Share)	$	11.46		$	12.05
Tax Liability ($ / Share)	$	7.95		$	8.35
Tax Liability Calculation
Pre-Tax Enterprise Value (LP+GP+Florida)	$	529.0		$	554.0
Tax Basis		(12.3	)		(12.3	)
Embedded Gain (Enterprise Value — Tax Basis)	$	516.7		$	541.7
NOL		(15.0	)		(15.0	)
Embedded Gain Post-NOL	$	501.7		$	526.7
Tax Liability @ 40.0%	$	200.7		$	210.7

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