Hey Ryan, I'm definitely no expert. I'll be bowhunting for turkeys for the first time this season but from what I'm reading arrow speed is the least important thing. In fact many guys reduce the poundage on their bow to be able to draw easier and with less movement. Having the arrow stay in the bird (not a pass through) is better from what I understand.
I'm going with heavier arrows, drop my bow from 70 to 60 lbs and get some Gobbler Getter (I think thats what they are) broadheads.
Let us know how your setup works so we can compare notes.
Good Luck hope you get a big ol gobbler!