Hey everyone I have a 292 stroker with MSD distributor.  I am running higher compression and was wondering on opinions about timing advance.  I am at 12 degrees btdc @ idle and 39 degrees 2500 rpm with vacuum advance unhooked.  With vacuum advance 49 degrees btdc.  I am getting preignition at random but I think that is because my fuel injectin system is slightly lean at times.  I was just wondering what other people have run for timing and if 39 degrees is too much.

Robi