Badger5 made me this, although I managed to completely mess up the dimensions so it wouldn't fit my car. Its a 63mm diameter, 60mm long alloy joiner with bead rolled ends. It has a boss welded to it to provide a take off point for vacuum / or a water meth nozzle point. The bung is untouched and you will need to drill and tap it to suit your requirements. £18 posted.