What you don't want to do is to go from normal landing flap 30/40 to flap 1. If you do, the 737 will just sink sluggishly downwards.
Boeing talks about engine failure on final and engine failiure during go-around. Flap one is recommended for all single engine go-arounds except when you get it just as you go-arround - for which flap 15 is recommended.