Search "Lump port modification" on whatever internet platform you use. The intake ports on the 230/250/292 cylinder heads have a big pillar right in the center of the port for a head bolt to pass through, That is removed, a shorter head bolt is installed at the bottom of the port, and some pretty sophisticated machining is done to change the shape of the port. An airfoil (lump) is added to change the routing of the intake mixture. It's primarily intended for better intake airflow at high engine speeds, along with a more radical camshaft and possibly higher compression than just installing the flat top pistons would provide. Unless you're going racing, the cost/benefit ratio is not good.
Jerry

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