Section clause (e) & (f) of 174 (2) reads as follows:
"The repeal of the said Acts and the amendment of the Finance Act, 1994 (32 of 1994.) (hereafter referred to as “such amendment” or “amended Act”, as the case may be) to the extent mentioned in the sub-section (1) or section 173 shall not-
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(e) affect any investigation, inquiry, verification (including scrutiny and audit), assessment proceedings, adjudication and any other legal proceedings or recovery of arrears or remedy in respect of any such duty, tax, surcharge, penalty, fine, interest, right, privilege, obligation, liability, forfeiture or punishment, as aforesaid, and any such investigation, inquiry, verification (including scrutiny and audit), assessment proceedings, adjudication and other legal proceedings or recovery of arrears or remedy may be instituted, continued or enforced, and any such tax, surcharge, penalty, fine, interest, forfeiture or punishment may be levied or imposed as if these Acts had not been so amended or repealed;
(f) affect any proceedings including that relating to an appeal, review or reference, instituted before on, or after the appointed day under the said amended Act or repealed Acts and such proceedings shall be continued under the said amended Act or repealed Acts as if this Act had not come into force and the said Acts had not been amended or repealed."
So, with regards to the query raised, Dept. has got "legal powers" to start investigation / inquiry and issue SCN under Finance Act, 1994 (32 of 1994)even after 01.07.2017 in my view.
These are ex facie views of mine and the same should not be construed as professional advice/suggestion.