Banshee - By David D. Beach. Jr.. The “Z” or 48-cu.-in. racing runabout is the smallest inboard raceboat recognized by the American Power Boat Association. This class is opening the door to organized racing for many boating enthusiasts because a complete racing outfit can be assembled for very little money. The 48‘s are probably the easiest-to—build race boats that are capable of really high performance, Class rules are fairly easy to comply with. They specify certain minimum hull dimensions ana say that the power plant must not have a displacement of more than 48 cubic inches. The most popular engine is the lightweight Crosley, suitably converted for marine use. When properly tuned up, it develops almost 40 hp and will drive Banshee at speeds up to 45 mph.