You do not need to be an Econ concentrator to break in, but you must know accounting and valuation. Buy these two books and memorize them:
Underwriting debt and equity issuances to fuel corporate expansion. the harvard college guide to investment banking pdf
If you have spent three hours searching with no luck, do not panic. The methodology is more important than the brand. You do not need to be an Econ
Bankers hire people they want to sit next to at 2 AM. Your GPA is table stakes (Harvard's median is ~3.6. Below a 3.4? You need a hook). the harvard college guide to investment banking pdf