The time from starting the process to getting a permit depends on many factors, and if you look at the time for renewal on an existing permit it gives you an idea of how slowly bureaucrats get things done.
Permit Review Report (112KB PDF file) Oct 21 2008 Nov 26 2012
Item K: Timely Application for the Renewal of Title V Permits - 6 NYCRR Part 201-6.3(a)(4) Owners and/or operators of facilities having an issued Title V permit shall submit a complete application at least 180 days, but not more than eighteen months, prior to the date of permit expiration for permit renewal purposes.
Item L: Certification by a Responsible Official - 6 NYCRR Part 201-6.3(d)(12) Any application, form, report or compliance certification required to be submitted pursuant to the federally enforceable portions of this permit shall contain a certification of truth, accuracy and completeness by a responsible official. This certification shall state that based on information and belief formed after reasonable inquiry, the statements and information in the document are true, accurate, and complete.