Be careful with that, I had one of those carts as a kid, with smaller tires on the rear, it would roll over very easy.
With those larger tires it is going to have more bite, and most likely will flip over real fast.
Ya I had a larger framed kart as a kid with the snowmobile motor setup. Wish I had a good picture of that monster. Mine had good wide rears to keep it upright.
That centrifugal clutch is crazy dangerous right there under yer armpit with no guard.