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                                                                   EXHIBIT 10.57


                              [LOGO] ALLIS-CHALMERS

                             7660 Woodway, Suite 200
                       Houston, Texas 77063 (713) 369-0550



                                  AMENDMENT TO
                            STOCK PURCHASE AGREEMENT


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                                DATED _____, 2004

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                                  AMENDMENT TO
                            STOCK PURCHASE AGREEMENT


         This AMENDMENT TO STOCK PURCHASE AGREEMENT (this "Agreement"), dated
_______, 2004, is made by and among Allis-Chalmers Corporation, a Delaware
corporation (the "Company"), and the signatories hereto (the "Investors").

                                    RECITALS

         WHEREAS, the Company and certain investors (the "Investors") have
executed and delivered to each other a Stock Purchase Agreement (the "Stock
Purchase Agreement") dated August 10, 2004;

         WHEREAS, certain Investors have requested that the Company enter into
certain additional covenants in connection with the transactions contemplated by
the Stock Purchase Agreement;

         WHEREAS, the Company has agreed to make such additional covenants for
the benefit of all Investors; and

         WHEREAS, the Company acknowledges that one or more Investors is
entering into the Stock Purchase Agreement in reliance upon the additional
covenants made by the Company herein;

                                    AGREEMENT

         NOW, THEREFORE, in consideration of the mutual covenants and agreements
set forth herein and for good and valuable consideration, the receipt and
adequacy of which are hereby acknowledged, the parties hereto agree as follows:

         1. ADDITIONAL SHARES. In the event the Company sells Additional Shares
of Common Stock (as defined below) within six months after the date hereof for a
price per share of less than $3.00 per share, then, and in each such event, the
Company shall issue additional shares (the "Additional Shares") of the Common
Stock to each Investor so that the average price paid by each Investor for the
Initial Shares and all Additional Shares issued to such Investor shall be the
same as the lowest per share price paid by any other person for Additional
Shares of Common Stock. The Additional Shares shall be "Shares" for all purposes
hereunder. As used herein, "Additional Shares of Common Stock" shall (a) include
the issuance of Common Stock by the Company, (b) include the issuance by the
Company of securities ("Convertible Securities") convertible into or
exchangeable for Common Stock, in which event the price deemed to be paid for
the underlying Common Stock shall be equal to the minimum amount that may be
paid for such Common Stock taking into account the amount paid for the
Convertible Securities as well as any additional amount payable upon exercise or
conversion of such Convertible Securities, but without taking into account
customary anti-dilution rights, and (c) not include the issuance of options and


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Common Stock pursuant to the agreements and other rights described in Schedule
2.6 hereof, including upon exercise of options granted in the future pursuant to
the Company's 2003 Incentive Stock Plan. The closing of the issuance of any
Additional Shares shall be effected at the offices of the Company on or prior to
the tenth business day following the date of issuance of any Additional Shares
of Common Stock triggering the issuance of Additional Shares. At the Closing,
the Company shall cause the Depository Trust Company to enter a book entry on
behalf of each Investor representing the Additional Shares issued to such
Investor.

         2. TRANSACTION RESTRICTIONS.

                  (a) The Shares may only be disposed of in compliance with
state and federal securities laws. In connection with any transfer of Shares
other than pursuant to an effective registration statement, to the Company, to
an Affiliate of an Investor or in connection with a pledge as contemplated in
Section 2(b), the Company may require the transferor thereof to provide to the
Company an opinion of counsel selected by the transferor, the form and substance
of which opinion shall be reasonably satisfactory to the Company, to the effect
that such transfer does not require registration of such transferred Shares
under the Securities Act. As a condition of transfer, any such transferee shall
agree in writing to be bound by the terms of this Agreement and shall have the
rights of an Investor under this Agreement.

                  (b) The Company acknowledges and agrees that an Investor may
from time to time pledge pursuant to a bona fide margin agreement with a
registered broker-dealer or grant a security interest in some or all of the
Shares to a financial institution that is an "accredited investor" as defined in
Rule 501(a) under the Securities Act and who agrees to be bound by the
provisions of this Agreement and, if required under the terms of such
arrangement, such Investor may transfer pledged or secured Shares to the
pledgees or secured parties. Such a pledge or transfer would not be subject to
approval of the Company and no legal opinion of legal counsel of the pledgee,
secured party or pledgor shall be required in connection therewith, provided
that the pledgee certifies to the Company that the requirements set forth in
this Section 2(b) are met. Further, no notice shall be required of such pledge.
At the appropriate Investor's expense, the Company will execute and deliver such
reasonable documentation as a pledgee or secured party of Shares may reasonably
request in connection with a pledge or transfer of the Shares, including, if the
Shares are subject to registration pursuant to this Agreement, the preparation
and filing of any required prospectus supplement under Rule 424(b)(3) under the
Securities Act or other applicable provision of the Securities Act to
appropriately amend the list of Selling Stockholders thereunder.

                  (c) Certificates evidencing the Shares shall not contain any
legend or stop transfer order, including the legend set forth in Section 1 of
the Stock Purchase Agreement: (i) while a registration statement (including the
Registration Statement) covering the resale of such Shares is effective under
the Securities Act, or (ii) following any sale of such Shares pursuant to Rule
144, or (iii) if such Shares are eligible for sale under Rule 144(k), or (iv) if
such legend is not required under applicable requirements of the Securities Act
(including judicial interpretations and pronouncements issued by the staff of
the SEC). The Company shall cause its counsel to issue a legal opinion to the
Company's transfer agent promptly after the Effective Date if required by the
Company's transfer agent to effect the removal of the legend hereunder. The
Company agrees that following the Effective Date or at such time as such legend


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is no longer required under this Section 2(c), it will, no later than five
business days following the delivery by an Investor to the Company or the
Company's transfer agent of a certificate representing Shares issued with a
restrictive legend (such date, the "Legend Removal Date"), deliver or cause to
be delivered to such Investor a certificate representing such Shares that is
free from all restrictive and other legends. The Company may not make any
notation on its records or give instructions to any transfer agent of the
Company that enlarge the restrictions on transfer set forth in this Section 2.

         3. SHELF REGISTRATION. The Company makes the following additional
covenants relating to the Registration Statement described in Section 6 of the
Stock Purchase Agreement:

                  (a) The Company shall prepare and file the Registration
Statement or cause the Registration Statement to be prepared and filed with the
SEC, as soon as practicable but in any event no later than thirty (30) days
after the date hereof, on Form S-3 or such other form as the Company is then
eligible to use for an offering to be made on a delayed or continuous basis
pursuant to Rule 415 of the Securities Act. The Company shall use its best
efforts to cause the Registration Statement to be declared effective under the
Securities Act no later than three (3) business days after receipt of notice of
"no review" by the SEC or one hundred twenty (120) days from the date hereof in
the event of SEC review. The Registration Statement may also register the sale
of shares of Common Stock of the Company by other Stockholders of the Company.

                  (b) The Company shall not suspend sales of Shares pursuant to
the Registration Statement for a period of more than thirty (30) days during any
twelve (12) month period pursuant to Section 6.2(e) of the Stock Purchase
Agreement.

                  (c) The Company shall pay to Investors, as liquidated damages
and as the sole remedy for the Company's failure to timely comply with such
obligations, a penalty of one percent (1.0%) of the amount paid for the Shares
by each Investor for the first thirty (30) day period of non-compliance, and a
penalty of two percent (2%) of the amount paid for the Shares by each Investor
for each subsequent thirty (30) days of non-compliance (if any period of
non-compliance exceeds thirty (30) days) with its obligation to timely file the
Registration Statement, to cause the Registration Statement to become effective
within the time periods set forth above, and to maintain the effectiveness of
the Registration Statement as set forth above.

         4. APPROVAL. This Amendment has been approved by Investors purchasing
at least 66-2/3% of the Shares to be purchased pursuant to the Stock Purchase
Agreement, as required by Section 9.9 of the Stock Purchase Agreement.

         5. INTERPRETATION. Except as modified hereby the Stock Purchase
Agreement remains in full force and effect.


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IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be executed
and delivered by their respective representatives hereunto duly authorized as of
the date first above written.


By:
Allis-Chalmers Corporation,                INVESTOR
a Delaware corporation
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                                           Signature
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Munawar H. Hidayatallah,
Chief Executive Officer                    ---------------------------------
7660 Woodway, Suite 200                    Name
Houston, Texas  77063
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                                           Title

                                           Address:

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                                           email


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