Years ago, Ansen made a aluminum 8 port head for the 62-70 Nova 153 cubic inch 4 cylinder motor.I can't remember if they were a crossflow head or not.Why don't you just go with one of the 2.5 GM engines that have a factory crossflow head already?---They have front and rear wheel drive types and are cheap to buy.Some have factory tubing headers.
EvilDr235