KiLLER K20 BUILD

Welcome to part three of the K20 build that we’re currently undertaking. Last issue, we prepped our scrapyard block ready for assembly and reported that our K24 RBB head has undergone some serious modifications, starting with blanking its rear to allow it to sit hard against the firewall in the midget. This is not something you’d do on any other form of engine, but it was needed here to get the motor sitting in the correct location.

Next, we shipped the head to Christchurch to spend time in the CNC at Horsepower Heads. As previously mentioned, the class rules in Western Springs F2 dictate that a 32mm restrictor must be used in each runner. With such a restriction, according to Horsepower Head’s Kevin Ban, the port sizes are crucial to maintaining velocity and charge momentum inside the port to promote good cylinder filling. Add