"Really what makes you say this?"
Because, you start putting high comp heads, pistons, carbs and all the rest to double the stock hp on just about any engine and the first thing to come apart will be the bottom end. Let alone a 230 with a 4+ inch stroke with all that poundage whirrling around.
Just listen to it rev...sounds labored to me. Not a lot of throttle response for something putting out double the hp.
Nothing was mentioned of any bottom end mods. Bottom ends on other modded engines with stock crank, rods, flywheels etc go up in smoke all the time....with much lighter components with much shorter strokes. Spend some time at the local drag strip some time. 6000 rpm AND 200 hp is an enormous strain to put on basically 1935 technology and expecting it to live long and prosper.
Without the proper ($$$$) components, my money says it will have a very short life on a dyno.
Not trying to start something. Just bench racin' here....with a lot of years of observing ...