Would Wearing a simple a pair of fancy black suit and pants make you blend in on any timeline in the past 3 centuries?

You would blend in until the late 1700's. The late 1700's were when long pants became the standard pant length for men. They very suddenly replaced the knee length breeches men wore prior to The French Revolution. Many socail changes lefd to the end of knee breeches -including their association with the french and other aristocracies. Previous to the 1790's your long pants and plain black coat would make you look like you belonged to an odd religion or an unusual sect. You could be labeled as a Quaker or an Anabaptist or worse -which would not have blended in at all. If you cut your pants off at the knee and shortened the jacket to the waist in front and lengthened the back you will have adapted your modern suit into something that would blend in from the late 1500's all the way to the end of the 1700's. For your shoes to fit in they would need large metal buckles and probably high heels.