Thanks mate. Thought this might be the case. Will try and track down a newy. It's a 13/16 bore. Anyone got one? For the record adapting a sunny booster is not a straight bolt on. Four holes need to be drilled through three layers of steel firewall, plus the master hole needs to be made substantially larger. Which is hours of fun with a drill, grinder and die grinder with limited space(insert sarcasm). The splitter also needs to be mounted to the strut tower. Two more holes to be drilled with limited space. This is not a huge deal. I would strongly suggest to anyone doing this conversion to do it with the engine out if possible. A plasma cutter would speed up the process a great deal. All the steel brake lines also need to be replaced as they run from the splitter as opposed to from the brass bias valve. Luckily this system was in a car I already had so I had everything to swap over. The car that had this system also had a modified brake pedal to accommodate the sunny booster plunger. The pedal has been cut recessed and welded. In hind sight I would have preferred to make a adapter plate to the existing bolt holes in the firewall and then a plunger bar of correct length for the standard brake pedal. Just thought I would add this info as there is a few points not mentioned in the teck wiki. And for the record my supposed soft H89 head is still working fine. I have checked the torque setting twice now. Nothing has loosened at all after @ 1000k's. Thanks again.