drivers side alternator bracket

[Leswig]

hello

A little help here.....I am wanting to put the drivers side alternator bracket back on the blazer, but apparently missing an integral part. My belt is not lining up correctly to the crank shaft pulley (its a double groove). I have the complete upper portion (attaches to the head and alternator).

What am I missing? I read a thread and saw a few pictures of a triple groove crank shaft pulley and a single+double crankshaft pulley. What is the correct answer to that riddle AND do you perhaps have a picture or two......and a hint as to where to buy the correct one.

thanks

Les