Invest extra take-home salary from tax cut or put into student loans?

With the new tax cut set to take effect in February, i'm estimating my paycheck to increase by $300/month. I'm currently paying $4,500 monthly towards $153k student loans @4.85%. I'm undecided right now as what to do with the extra income. I'm leaning towards investing the $300 extra from tax cut into safe dividend blue chips stocks and use DRIP. This will serve as potential emergency fund. I already committed 70% of my take home pay towards student loans. Should I put the extra $300 into... Invest extra take-home salary from tax cut or put into student loans?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums