I have an arrow weight of 391 grains. I am getting 262 fps out of my bow and am shooting a whisker biscuit rest.

If I switch to feathers, will I gain much speed? But, will I sacrifice enough weight to cancel my KE out? Is 391 grains a fairly light arrow? Oh yeah, it is 26.5" in length and using 100 grain montecs. (391) includes broadhead

Cotton