On the old Clinton go-cart engines, the round transfer ports were squared up and the dividers thinned as much as possible. IIRC, the intakes were squared on the bottom only, or the intake timing was changed too much. That's about the era that I gave up on two-strokes! I hate 'em! Any sled I ever took for a drive, I ended up walking home.
My brother had a 440 TNT, seemed like a good runner. We put the engine in a newer Free-air sled, aluminum instead of steel frame. Not as tough, but lots faster.