This insert has a higher volume / lower compression ratio than our VHM standard insert, meaning better overrevolution characteristics and more top speed. However, keep in mind that this compromises bottom power reaction. The combustion chamber fits the VHM cylinder head perfectly and is easy to change. The last numbers of the part number are engraved to the insert for identification.
Use in combination with VHM head AA33157
This insert does not fit into an OEM head, only a VHM cylinder head.