I wanna say SHA clamp size is 19.mm. and PHBG is... I don't know, but ALL PHBG's 16mm-21mm have the same body and clamp so the clamp couldn't be less than 23. right? either way one doesn't fit on the other's intake. on a side note I wouldn't complain about carb quality and then buy a cheep knock off, guess why its cheep.