Start with the birth certificate for your particular bow not the IBO speed rating which is between 314 and 322 not just 322. (Don't want to mislead you).

A person loses about 10 fps for every inch of draw length below 30 inches. That would mean a 40 fps drop in arrow speed right off the bat because of your 26 inch draw length. Throw in 50 grains in arrow weight over IBO specs at 70 lbs and you are losing another 17 fps. That is a total of 57 fps. Subtract that from 314 and you get 257 fps. Subtract that from 322 and you get 265 fps.

Ofcourse that is assuming a bare bow string except for a tied-on nockset.