You've got energy to spare. If you want to get a faster arrow, you won't lose much KE. You can probably go to 350gr and not have less than 95lb-ft KE. On the other hand, you'd have to have an arrow that is well below 5gr/lb in order to get to the speed you are looking for. You might be able to pick up 10-15fps, but that is about it.

Good luck.