The Racing Beat Intake Port Templates allow you to undertake your own "J-bridge" port efforts on any 12A or 13B rotary engine (except 13B 6-port). These templates are traced from Racing Beat's own master templates, which are the result of years of research and development. The actual port shapes are traced on thin sheets of aluminum which you must first cut out, testing your ability to use a die grinder effectively before attempting to port an expensive engine component. The finished template is held in place and the porting shape is then traced onto each housing. You must then use your own judgment to develop the port shape beyond the scribed line.