Faster Team Shadow

I'm looking to make a 91 team shadow 21 boat faster. Specs are: 225 vindicator sitting 2 inches below pad on a 4 inch jackplate. 24p raker and a 24p 4 blade pt. The boat is ran in light chop at 60-63 on gps. I would like to see at least 70. Should this boat be faster? I read that setback brackets would help but I'm not sure if it will get the boat to 70.

I have 1990 Team Shadow same motor CMC jackplate top speed 61 mph.
The boat is heavy, I cut a hole to install a horn on the side and it's over an inch thick.
I'm also thinking of more set back but ultimately it needs more horsepower.