Setup/Engine advice for "fast" jon boat

[TooQuick]

Hello, I am a rookie with a lot of questions in search of some advice for setting up for my 14' aluminum flat/jon boat from the brf community!

I primarily want something to run out in the bayou with that's bare bones and fast. Give me some general tips on the whole set up. With your experience, how would you do it if you were doing it? Which engines are easily findable/modifiable, cost/weight effective? What mods would you do on which engine and what to stay away from?

I'm leaning towards getting a 90's 70hp 2-stroke Yamaha non tiller handle and doing some basic mods ( increase timing, carbs, mil the head, tuner, prop, nose cone (if it will help) and etc.. ) Also want to swap the lower unit to a (Yamaha 55 twin OR a Mariner 48, 55 or 60 twin) for the shorter gearing, since this boat will be fairly light and mostly ran at higher speeds. or a yammie 90 minus the carbs and unit swap.


Other notes:
After it is up in running I will then spec a prop out (cleaver or whatever is best fitting.)
It will have a jack plate (4" set back.)
A water pressure gauge (if necessary.)
It's relatively light for a ole' flat boat (5 gallon tank, one bench, lawn mower battery, no floor, no anything.)
I'm cutting the wood out the transom and rebuilding/reinforcing it with alum. 2x2's and plate (should i make it taller?)
Also where is good place to find outboards in Louisiana? (besides La sportsman and craig's list.) I'm not opposed to buying a old engine also.
What is a achievable top speed? (I'd like to see at least 45mph.)

THANK YOU, ANY INPUT IS APPRECIATED.

*This is before I removed the middle bench and removed the unnecessary small stuff*
Can

[sltx9]

Put a evinrude sst60 or short shaft stinger on her. That should get her going. Lol

[Krazy Karl]

It wouldn't take much to make that boat downright dangerous. Can you say 'blowover'? Not fun.
kk

[HTarver]

what is that, a 12x48 you should have no problem running 45mph wit a STOCK 40hp and the right prop/setup. I run a 13x44 flat bottom like this one with a modified 40 mercury, it runs in the low 70s.

[TooQuick]

its a alweld 1448 i believe. Nice, how much set back you run HTarver?