I would say that attacking 3 B-17's is a bad idea as a single plane a 27K.
The B-17 reaches 300mph at 30K so you were almost at it's top speed and at 27K I would say your plane would be handling like a dead fish, just catching them and being sluggish. While the bombers are at alt and cruising waiting for you to make a pass.
At the very least I would get a 152, spit-14, P51 or P38 up to chase them down and even then it would not be the best thing to do alone..