I have no idea of your finished arrow weight, if I did I could make a guess because I had that exact bow.....and it was ROCKET.[:-]
Mine at 30"/71# would shoot my 355gr test arrows at 333fps with a loop ,and leeches.
A 475gr Terminator Hunter Select whipped through at 290fps![8D]
If you are at 5grs /lb you're in the 320's. and into the 80+ ft/lb of KE range