need help

I have a 91 si hatch with a d16y7. The problem that im having is finding a alternator belt that will work with this setup. I am using the alternator from my si cause i tried to use the one that came with the engine and the connector is different. Has anybody run into this problem? I have tried using the belt form a y7 engine and it breaks on me cause its to wide for the alternator pulley, i have also tried the original belt and that was too short. Please let me know what i can do to fix this. thanks in advance

are the pulleys differnt? if they are you will need to change the pulleys for them to be the same. Then use a piece of string and go all the way around the pulleys (just like the belt will) and then mark how far it is around, measure it then go to the parts store and tell them you need a belt that size.

the thing is that the shaft is also diff if i put both the alternators next to each other the one for the y7 is bigger. so i would also have to change the shaft. thanks for the info any other ideas