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                                                                  EXHIBIT 99.3
 
                                October 2, 1996
 
STRICTLY CONFIDENTIAL
 
United Dominion Industries
2300 One First Union Center
Charlotte, NC 28202-6039
 
Attention:
 
Gentlemen:
 
     In connection with your consideration of a possible negotiated transaction
with Core Industries Inc and/or its subsidiaries, affiliates and divisions
(collectively, the "Company"), you have requested information which is not
readily available to the general public concerning the Company. As a condition
to your being furnished such information, you agree to treat any information
concerning the Company which is furnished to you by the Company or on behalf of
the Company by its representatives, whether furnished before or after the date
of this letter agreement (herein collectively referred to as the "Evaluation
Material"), in accordance with the provisions of this letter agreement. For the
purposes of this letter agreement, the term "Evaluation Material" includes all
data, reports, interpretations, forecasts, audit reports and other records to
the extent that they include information concerning the Company which is not
readily available to the general public, and also includes all notes, analyses,
studies, compilations, interpretations or other documents prepared by you or by
your directors, officers, employees, representatives or advisors which contain,
reflect or are based upon, in whole or in part, the information furnished
pursuant to this letter agreement. The term "Evaluation Material" does not
include information which (i) was or becomes generally available to the public
other than as a result of a disclosure by you or your directors, officers,
employees, agents or advisors, or (ii) was or becomes available to you on a non-
confidential basis from a source other than the Company or its advisors provided
that such source is not to your knowledge bound by a confidentiality agreement
with the Company, or (iii) was within your possession prior to its being
furnished to you by or on behalf of the Company, provided that the source of
such information was not to your knowledge bound by a confidentiality agreement
with the Company in respect thereof.
 
     (1) You hereby agree that the Evaluation Material will be used solely for
the purpose of evaluating a possible negotiated transaction between the Company
and you, and that such information will be kept confidential by you and your
directors, officers, employees, representatives and advisors; provided, however,
that (i) any such information may be disclosed to your directors, officers,
employees and your representatives or your advisors for the purpose of
evaluating a possible transaction between the Company and you (it being agreed
that such directors, officers, employees, representatives and advisors shall be
informed by you of the confidential nature of such information and you shall
cause them to treat such information confidentially and shall maintain a list of
those to whom such information has been disclosed which list you will present to
us upon request) and (ii) any disclosure of such information may be made to
which we consent in writing. In any event, you shall be responsible for any
breach of this letter agreement by any of your directors, officers, employees,
representatives or advisors and you agree, at your sole expense, to take all
reasonable measures (including but not limited to count proceedings) to restrain
such directors, officers, employees, representatives and advisors from
prohibited or unauthorized disclosure or use of the Evaluation Material.
 
     (2) Without the prior written consent of the Company, except as required by
law or applicable stock exchange regulation, you will not, and will direct such
directors, officers, employees and representatives not to, disclose to any
person either the fact that discussions or negotiations are taking place
concerning a possible transaction between the Company and you or any or the
terms, conditions or other facts with respect to any such possible transaction,
including the status thereof. The term "person" as used in this letter agreement
shall be broadly interpreted to include without limitation the media and any
corporation, company, group, partnership, other entity or individual.
 
     (3) You hereby acknowledge that you are aware, and that you will advise
your directors, officers, employees, agents, representatives and advisors who
are informed as to the matters which are the subject of this
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letter agreement, that the United States securities laws prohibit any person who
has material, non-public information concerning the matters which are the
subject of this letter agreement from purchasing or selling securities of a
company which may be a party to a transaction of the type contemplated by this
letter agreement or from communicating such information to any other person
under circumstances in which it is reasonably foreseeable that such person is
likely to purchase or sell such securities.
 
     (4) In the event that you are requested or required (by oral questions,
interrogatories, requests for information or documents, subpoena, civil
investigative demand or similar process) to disclose any information supplied to
you in the course of your dealings with the Company or its representatives, it
is agreed that you will (i) provide the Company with prompt notice of such
request(s) and the documents requested thereby so that the Company may seek an
appropriate protective order and/or waive your compliance with the provisions of
this letter agreement and (ii) consult with the Company on the advisability or
taking legally available steps to resist or narrow such request. It is further
agreed that, if in the absence of a protective order or the receipt of a waiver
hereunder you are nonetheless, in the written opinion of your counsel, compelled
to disclose information concerning the Company to any tribunal or else stand
liable for contempt or risk other censure or penalty, you may disclose such
information to such tribunal without liability hereunder; provided, however,
that you shall give the Company written notice of the information to be so
disclosed as far in advance of its disclosure as is practicable and shall use
your best efforts to obtain an order or other reliable assurance that
confidential treatment will be accorded to such portion of the information
required to be disclosed as the Company designates.
 
     (5) You hereby acknowledge that the Evaluation Material is being furnished
to you in consideration of your agreement that, for a period of three years from
the date hereof neither you nor any of your affiliates (as such term is defined
under the Securities Exchange Act of 1934, as amended (the "1934 Act")) will in
any manner, directly or indirectly: (a) effect or seek, offer or propose
(whether publicly or otherwise) to effect, or cause or participate in or in any
way assist any other person to effect or seek, offer or propose (whether
publicly or otherwise) to effect or participate in, (i) any acquisition of any
securities (or beneficial ownership thereof) or assets of the Company; (ii) any
tender or exchange offer, merger or other business combination involving the
Company; (iii) any recapitalization, restructuring, liquidation, dissolution or
other extraordinary transaction with respect to the Company; or (iv) any
"solicitation" of "proxies" (as such terms are used in the proxy rules of the
Securities and Exchange Commission) or consents to vote any voting securities of
the Company; (b) form, join or in any way participate in a "group" (as defined
under the 1934 Act); (c) otherwise act, alone or in concert with others, to seek
to control or influence the management, Board of Directors or policies of the
Company, (d) take any action which might force the Company to make a public
announcement regarding any of the types of matters set forth in (a) above; or
(e) enter into any discussions or arrangements with any third party with respect
to any of the foregoing. You also agree during such period not to request the
Company (or its directors, officers, employees or agents), directly or
indirectly, to amend or waive any provision of this paragraph (including this
sentence).
 
     (6) You agree that you will have no discussion, correspondence, or other
contract concerning the Company or its securities or any transaction with or
concerning the Company or its securities except with the management of the
Company and its designated representatives or except as otherwise contemplated
by this letter agreement; provided, however, it is understood and agreed that
you may retain one or more third party advisors to do industry-wide studies to
gain information about the competitors and customers in the industry, including
the Company. In consideration of the Evaluation Material being furnished to you,
you hereby agree that, for a period of one year from the date hereof, none of
your employees who gain access to the Evaluation Material and no employee
resident in your Charlotte, NC corporate office, directly or indirectly will
solicit to employ any of the current officers or employees of the Company,
without obtaining the prior written consent of the Company. You further
acknowledge and agree that the Company reserves the right, in its sole and
absolute discretion, to reject any or all proposals and to terminate discussions
and negotiations with, or directly or indirectly involving, you at any time.
 
     (7) At any time upon our request you shall promptly redeliver to the
Company all written material containing or reflecting any information contained
in the Evaluation Material (whether prepared by the Company or otherwise, and
whether in your possession or the possession of your directors, officers,
employees, or advisors, but except items prepared by you or your advisors) and
will not retain any copies, extracts or other reproductions in whole or in part
of such written material. All documents, memoranda, notes and other writings
whatsoever
 
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(including all copies, extracts or other reproductions), prepared by you or your
advisors based on the information contained in the Evaluation Material shall be
destroyed, promptly upon your determination to discontinue consideration of a
transaction with the Company, or upon request by the Company. The redelivery of
such material shall not relieve your obligation of confidentiality or other
obligations hereunder.
 
     (8) Although we will endeavor to include in the Evaluation Material
information known to us which we believe to be relevant for the purpose of your
investigation, you understand that the Company makes no representation or
warranty as to the accuracy or completeness of the Evaluation Material. You
agree that neither the Company nor its representatives shall have any liability
to you or any of your representatives resulting from the use of the Evaluation
Material supplied by us or our representatives except pursuant to a
representation or warranty contained in a binding agreement between the Company
and you.
 
     (9) It is further understood and agreed that no failure or delay by the
Company in exercising any right, power or privilege hereunder shall operate as a
waiver thereof nor shall any single or partial exercise thereof preclude any
other or further exercise of any right, power or privilege.
 
     (10) It is further understood and agreed that money damages may not be a
sufficient remedy for any breach of this letter agreement by you or by any of
your agents or representatives and that the Company shall be entitled to seek
specific performance and injunctive or other equitable relief as a remedy for
any such breach, and you further agree to waive any requirement for the securing
or posting of any bond in connection with such remedy. Such remedy shall not be
deemed to be the exclusive remedy for your breach of this letter agreement, but
shall be in addition to all other remedies available at law or equity to the
Company. In the event of litigation relating to this letter agreement, if a
court of competent jurisdiction determines that you or any of your agents or
representatives have breached this letter agreement and such determination is
final, then you shall be liable to pay the Company the reasonable fees incurred
by the Company in connection with such litigation, including any appeal
therefrom.
 
     (11) This letter agreement and all disputes arising from or relating to
this letter agreement shall be governed by and construed in accordance with the
internal laws of the State of Michigan, without giving effect to the principles
of conflict of laws thereof. You also hereby irrevocably and unconditionally
consent to submit to the jurisdiction of the courts of the State of Michigan for
any actions, suits or proceedings arising out of or relating to this agreement,
and further agree that service of any process, summons, notice or document by
U.S. registered mail to your address set forth above shall be effective service
of process for any action, suit or proceeding brought against you in any such
court. You hereby irrevocably and unconditionally waive any objection to the
laying of venue of any action, suit or proceeding arising out of this letter
agreement or the transactions contemplated hereby in the courts of the State of
Michigan or the United States of America located in the State of Michigan, and
hereby further irrevocably and unconditionally waive and agree not to plead or
claim in any such court that any such action, suit or proceeding brought in any
such court has been brought in an inconvenient forum.
 
     This agreement and all obligations hereunder shall continue in effect in
accordance with its terms for a period of five (5) years from the date hereof or
until terminated in writing by the Company.
 
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     If you are in agreement with the foregoing, please so indicate by signing
and returning one copy of this letter agreement, whereupon it will constitute
our agreement with respect to the subject matter hereof.
 
                                          Very truly yours,
 
                                          CORE INDUSTRIES INC
 
                                          By:      /s/ LAWRENCE J. MURPHY
                                            ------------------------------------
                                            Its: Executive Vice President
 
Confirmed and Agreed to:
 
United Dominion Industries, Inc.
 
By:      /s/ J. MILTON CHILDRESS
    ----------------------------------
    Its: Vice President
 
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