First off,1.9 60's aint too shabby!! 2nd,bumping your timing wont make you a full second faster,you might get a tenth. Yeah,with those heads and custom cam( Hopefully you matched it well to the heads) you should be at least in the low 13's,even high 12's!! It sounds like you sank some cash into your stang.Do the next easiest thing.Spend a 100 bucks and get it dynoed.They can tell where the problem lies,tell you your perfect shift points,your HP at the wheels,and they can see if your combo is working.The cam you have mite require more gear.Was your maf calibrated for 24lbs. injectors?Your fuel pressure sounds fine,the dyno will tell you