The result of your conversion between pound/cubic yard and grain/quart [US] appears here
To convert between Pound/cubic Yard and Grain/quart [US] you have to do the following:
First divide 0.45359237/((0.0037854118/231)*1728*27) / ((0.45359237/16)*(192/175)/480)/(0.0037854118/4) = 8.66448045
Then multiply the amount of Pound/cubic Yard you want to convert to Grain/quart [US], use the chart below to guide you.
Symbol: lb/yd³
No description
Symbol: gr/qt
No description