3 The Panhandle main support system is mocked up here. Like honing the cylinder bores, the main bore will be honed with the main support in place, just like when the engine is in the car and running. The main cap machining allows the support to have greater surface contact with the main caps. The main support is made from 4140 chromoly steel and is 0.375-inches thick. The design clears most oil pans.