Most TAG Cadet classes run at 245. Most drivers run at 248-250 to be safe on weight. If you can get to 255 you can compete. With a 90 pound driver and 15 pounds of weight we ran at 248 or so.
You can hit ten pounds with some basic changes – 3.0 axle (assuming you are running a 5.0 like most current karts), mag front and rear hubs, mag sprocket carrier & engine mount, MXC or the new Swift wheels. Tillett T5 VTi seat is about as light as you can find. No graphics, no data in race trim, no heel stop (shouldn’t need it for a tall driver). May be able to order a kart unpainted. Fastech has a ton of titanium available if you really need an extra pound or two.
We have made some bigger kids pretty darn competitive – just takes some effort. Pick a good kart and make it light. Don’t pick a kart just for weight.