Swinny, you're dead on! Costx1.43 = 30% Gross Profit on part sold. This year I'm shooting for an Avg. GP of 50%. or higher. Some other #s are: Cx1.53=35%, Cx1.67=40%, Cx1.82=45%, Cx2.0=50%, etc. Sell less expensive parts at a higher GP to make up for a lower G... Login to read more.