I searched moates site for bins and found 3 different bins,all were for an 89 350 auto 327 gears which is what my car is........apyu,aujn,aujm,all are 6e mask.Anyone know what the difference is? Is one any better than the other?

use your editing software (tunerpro,tunercat,etc)to open the bins and take a good look at the timing tables etc. you will be able to pick one on your own..