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I wouldn’t be surprised that we already have one or two that are there or very close.
You will need a very strong powerhead ...either a Bridgeport or oval port will work. You need horsepower at over 7500 rpm. You will need a perfect crank to make hp at and above 7500 rpm. Simply stated a perfect crank is one where the motor doesn’t fight itself at high rpm. Any crank is fine at 6000 rpm, but at 7500 rpm all the pistons have to be going in the same direction all the time, you can’t have one going in the opposite direction even for an instant. That instant causes the motor to fight itself and you lose horsepower and rpm.
With a 1:87 gearcase you will need 24 pitch and between 12 & 12.5 diameter.
I would run a critchfield hull.
I think if you have a 77 to 78 mph boat now. Transom water pickup and a larger skeg will enable you to run higher on the transom with the gearcase bullet above the water. You will be able to turn a 24 pitch and exceed 80 mph.
You can’t get more hp out of the motor so you reduce the drag on the gearcase in the water to increase the speed.
Owen Boris had the world Mod VP speed record running elongated gearcases. I don’t think the SST 60 gearcase is long enough to make a difference. A nose cone with low water pickups will get two or three mph extra.
If you wanted to reduce transom weight of the motor switch to a lighter clamp bracket and no power trim. You don’t need positive trim at 75 mph plus in a TBoat.
You could try a light power jack plate. Then you can adjust the height while underway.

You’re pushing the boat to it’s limit and if you don’t have the driving skill at 70 plus mph don’t even think about going faster. Know you’re limitations!.