Homemade GoKart

OK guys so ive been planning this gokart for a little while now. Its going to be very soon that i start construction on it. for the body i am using box steel. single level frame. not a multi level frame. using axles, steering and tires off of an old racing kart i salvaged (been wrecked so many times its useless, otherwise i would use that)
Originally i planned on using a 5hp briggs flathead and a comet torque converter or a centrifugal clutch. then I came across an old 8hp flathead briggs and planned on using it with the comet torque converter. then i went to start it up and realized it was missing the entire valve train. So the 8hp went out of the question. Then i came across an old cub cadet 1440. hydro with bad seals (pumps the oil out faster than you can put it in) and a 14hp vtwin ohv briggs vanguard. this vanguard has 730 total hours, but was completely overhauled at 700 hours. it did sit for 11 years, but the engine is free, has clean oil and good compression. i think i forgot to mention too that its a 1994. Then i had the idea to put that engine on my gokart, since i have it and itll just be sitting around anyway because none of my mowers use horizontal shaft engines. I was thinking mount it like a normal engine. My biggest question is- Do they make centrifugal clutches or torque converters for a one inch shaft? if not, i was planning on doing a 5 inch pulley on the crank driving a 4 inch pulley on a 3/4 shaft which will run on pillow bearings. on the other end of the shaft do a centrifugal clutch with a 12 tooth sprocket driving the 25 tooth sprocket already on the axle.
For exhaust on the engine i think i will do straightpipes pointing straight backwards. they would go about 2 inches out from the engine and then bend backwards. the front cylinder will go out a little farther than the front. i want them to sit side by side like a double barrel shotgun. not super loud for the driver, but deafening for anyone behind me. (yes i will be mounting the exhaust pipes to the engine so that they do not break off from the cylinder) i will probably weld up a bracket for them and mount the bracket with the bolt that holds the engine down.

Comments or suggestions or ways i could do this better? Anything is helpful

BMI carts would have the centrifugal clutch for the 1 inch shaft, around the $100 price range though.

Personally with that much power I would go with the torque converter. Maybe a Chinese clone of a comet, or pull one from a junk atv or snowmobile? Add that to the list of things to get when we hit up junkyards haha

Little update on plans for this thing. The mini quad we are cutting up for the Dynamark will donate the front of the frame to this. Meaning that we will have independent front suspension. Now a rack and pinion and a torque converter from a junk gas golf cart will be perfect. Not sure quite on the rear end or what tires will be going on here but those will come later. More to come once the weather warms up