The string loop itself will add a little weight to the string so might slow things down about 1-2 fps, but to maintain the same anchor points as yu now have you would have to shorten the draw length (cam) by about 1/2" and this will cost you another 5 fps or so.
Your best bet is to leave the bow's draw length alone. Try choosing new. properly spined arrows that the total weight would equal 5 gr per pound of draw weight.
Clean any accessories off the string that you don't need such as a kisser button and/or a peep using a rubber tube. String silencers are a no-no. Shorten the center serving to about 3", 1 1/2" above and 1 1/2" below the nocking point or there abouts.
It's possible, but no guarantee that a good set of custom string madfe from BCY 8125 could gain as much as 10 fps. Play around with speed nocks on the string, which requires the use of a chrono to find the sweet spot.
Lastly, super tune your bow for the very best arrow flight as a wobbling arrow scrubs speed down range.
When all else fails go buy a bow with a faster IBO rating. The faster the better. You can always find easy ways to slow one down, but it can be a bugger trying to eke the last fps out of a slower bow.