More words: Must be blueprinted because stock production tolerance are absurdly poor, so you have to add about $500 to the price. Still, there’s a ton of them out there and you might want to try it as used ones can be found cheap. I’m 190lbs and find them fun but not very quick off the line. You might be too much. We have a guy who runs a KT100 in our TaG class, at a 320lb total weight versus our 390. It ain’t even close.
Another possibility: A complete, rebuilt 28hp Leopard system for $1000. http://www.italianmotorsusa.com/collections/used-items/products/used-leopard-engine-kits
I believe that’s a turn-key package. All you need is an axle sprocket. Rebuild cycle is roughly 20 hours, but that is a LOT of hot lapping. I’ve seen some big guys (like 250-260) turn decent laps in them.