Well, to answer your original question, disregarding whether or not you should get a PHBG:
The SHA clamp on intakes probably won't fit a PHBG. The chamber that clamps to/over the intake on a PHBG is much larger, regardless of the actual bore of the carb. For instance, my 16mm PHBG fits over a 19mm Polini intake, and still needs some spacer in the clamp tube to make it fit snugly. My 14mm SHA fit on a 15mm intake snugly.
In a nutshell:
- PHBG Carburetors have a spigot/clamp tube LARGER than the actual bore size where it connects to the intake
- SHA Carburetors have a clamp tube that is the same size as the bore of the intake
Hope this helps you.