Rumors are spilling over and over since the ISTAT Americas conference in March that Boeing is seriously looking at the P&W GTF as a second engine option in addition to the LEAP-1B for the B737MAX. Aspire Aviation has a long article about the ongoing optimisation of the MAX here and Scott Hamilton is quoted in an article by the New Mexico Business Weekly here. A reason for these rumors seems to be the lack of confirmed orders for the MAX so far. There are only three customers who have ordered the MAX, all others only delivered commitments to the Boeing Headquarter so far. Sure, the year is long, so there is enough time for Boeing to convert the commitments to firm and credible orders, especially as Boeing might be keen to make a similar splash with the MAX at Farnborough as Airbus did with the Neo at Le Bourget last year. But as now there are these rumors about a possible second engine, the committed customers might want to wait and see if there is some truth behind them. So firming up the commitments before there is a final word from Boeing (or P&WA) in either way might be a challenge.
Scott Hamilton expects a decision in the next months - that could also coincide with Farnborough...