change ignition timing?

i have a 75 280z with FI and some mods and i just finished my install of all new timing components and a stage 3 cam kit from MSA and was wondering if the ignition timing still should be set to stock or if it should be altered? if so does anyone know how it should be altered? i ask this because today when timing it it seemed to run not as well with the factory setting of 10 degrees btdc it ran smoother with a setting nearer to tdc but im no expert and wouldnt dare leave the timing at anything but stock unless its alright to do so. thanks.~Jerrod