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                                                                     EXHIBIT 8.1
 
                  [LETTERHEAD OF MORGAN, LEWIS & BOCKIUS LLP ]
 
                                 March 1, 1999
 
The FINOVA Group Inc.
1850 N. Central Avenue, No. 1159
P.O. Box 2209
Phoenix, Arizona 85004
 
Ladies and Gentlemen:
 
     Pursuant to an Agreement and Plan of Merger dated as of January 6, 1999
(the "Merger Agreement") among The FINOVA Group Inc., a Delaware corporation
("FINOVA"), FINOVA Newco Inc., a Delaware corporation ("Merger Sub") and Sirrom
Capital Corporation, a Tennessee corporation ("Sirrom"), Merger Sub will merge
with and into Sirrom (the "Merger").
 
     We have acted as counsel to FINOVA in connection with the Merger and in
that connection, you have requested our opinion as to the accuracy of the
description in the registration statement of FINOVA filed March 1, 1999 (the
"Registration Statement") of the material federal income tax consequences of the
Merger to FINOVA. In rendering our opinion, we have examined the Merger
Agreement, the Registration Statement, and such other documents and corporate
records as we have deemed necessary or appropriate. In addition, we have assumed
(i) the Merger will be consummated in the manner contemplated in the
Registration Statement and in accordance with the provisions of the Merger
Agreement, (ii) the statements concerning the Merger set forth in the
Registration Statement are accurate and complete, (iii) we will deliver an
opinion (the "Tax Opinion") to you on the date of closing pursuant to Section
5.3(h) of the Merger Agreement, based upon reasonably requested representation
letters, to the effect that (a) the Merger constitutes a reorganization within
the meaning of Section 368(a) of the Internal Revenue Code of 1986, as amended
(the "Code"), (b) FINOVA, Merger Sub and Sirrom will each be a party to the
reorganization within the meaning of Section 368(b) of the Code, and (c) FINOVA,
Merger Sub and Sirrom will not recognize gain or loss for U.S. federal income
tax purposes as a result of the Merger; and (iv) the Merger will be treated for
federal income tax purposes in accordance with the Tax Opinion.
 
     Under current law and on the basis and subject to (i) the accuracy of the
statements and representations contained in the materials referred to above and
the above assumptions and (ii) our considerations of such other matters as we
have deemed necessary, in our opinion the discussion of the material federal
income tax consequences of the Merger to FINOVA and Merger Sub in the
Registration Statement under the headings "Summary -- Material Federal Income
Tax Consequences" and "Material Federal Income Tax Consequences" is correct. You
have not requested, and we do not express, an opinion concerning any other tax
consequences of the Merger.
 
     This opinion expresses our views only as to U.S. federal income tax laws in
effect as of the date hereof. It represents our best legal judgment as to the
matters addressed herein, but is not binding on the Internal Revenue Service or
the courts. Accordingly, no assurance can be given that the opinion expressed
herein, if contested, would be sustained by a court. Furthermore, the
authorities upon which we rely are subject to change either prospectively or
retroactively, and any change in such authorities or variation or difference in
the facts from those on which we rely and assume as correct, as set forth above,
might affect the conclusions stated herein.
 
     This opinion is not to be used, circulated, quoted or otherwise referred to
for any purpose without our express written permission. We hereby consent to the
filing of this opinion as an exhibit to the Registration Statement and to the
reference to us in the section captioned "Material Federal Income Tax
Consequences" in the Registration Statement. In giving this
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consent we do not hereby admit that we come within the category of persons whose
consent is required under Section 7 of the Securities Act of 1933, as amended,
or the rules and regulations of the Securities and Exchange Commission
thereunder.
 
                                          Very truly yours,
 
                                          /s/ MORGAN, LEWIS & BOCKIUS LLP
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                                          Morgan, Lewis & Bockius LLP