Custom cuts available. If you want the whole transmission case that is possible as well. Automatic starters are suggested for use with these cases as the bushing area may be enlarged. For 6V you may use automatic starter: 141911021 The 12V Automatic starter is SR17X. When I cut these I pull the next one off the pile. Bushing holes are not guaranteed which is why I suggest the automatic starter. I do not clean the core so it may be a bit dirty from previous use or sitting outside.