Upgrade to dual diaphragm booster bolt pattern

[hogvan]

Hi all,

I"m wanting to upgrade my brake booster and master cylinder but unsure what bolt pattern will fit my hq, most universal ones i've seen state they are 4 bolt pattern 3 3/8 inch apart or 3 1/2 inch apart. I'm wondering what others have done out there? what size fits etc?

[HK1837]

HT-HG one will probably bolt it but you'd have to play around with the pushrod to get the right one for a HQ pedal.