Hydroboost problem

Hard to tell from your description so back to basics, if the H/boost has 3 ports PS pump has 1 H/press and 1 return port, H/boost has H/press in and out and 1 return port, steering gear has 1 H/press and 1 return port. You should run a cooler, maybe you are? So, pump H/P line to H/boost inlet, outlet to gear then to cooler, now both return lines couple together and back to pump return or add another return port to pump reservoir and disregard coupler.
I've been wrong before so you should follow kit instructions if you do get any.
It sounds like you can get a bigger cam now.