I"d use the SU that Auto-Meter supplied and just re cut the threads on the fitting in the kit. I have the Auto-Meter mechanical OP gauge and the the fitting for the block was so damn close and it being brass I ran the proper die over it and threaded right in. I dont remember of the top of my head what the threads are but IIRC its BSP not metric. I can go look here in a few if you want.
