Simple with the following generalizations. Start with the IBO speed for your bow. I believe it to be around 295 fps.

Subtract 10 fps for every inch of draw length you are below the 30 inch "test standard". In your case that means a loss of speed of about 20 fps.

Next subtract approximately 1 fps for every 3-4 grains of arrow weight you are above the IBO "test standard" arrow weight of 350 grains. (a 460 grain arrow would cost you about 27-34 fps)

Next add or subtract approximately 1.75 fps for every pound of draw weigth you are eitherover or under, respectively, the IBO "test standard" weight of 70 pounds. In your case that means you gain approximately 8-9 fps.

Lastly, subtract approximately 4-5 fps for every string accessory you have installed on the bow...peep sight, string silencers, string loop, etc...

Then take all of those numbers and subtract/add them to your IBO speed rating to determine a fair estimate as to your speed.