Not to burst your bubble but 70 is a pretty tall order for a boat that big and heavy. I would start with a set of through transom headers and definitely add a droop snoot, place divereter, and ride plate and shoe. How tight is the pump? When was it rebuilt or has it been? What are the specs on the motor? Is it stock and how much HP? These are all ?'s needing answered to help you on your quest. This boat looks more like a good family cruiser than a candidate for high speed action. Not trying to kill a dream just saying you are going to have to spend a lot of money and time while exhibiting patience experimenting with different set-ups to get that speed. Another area to look into is changing the loader.