I understand that every 911 came with one of these. Its a wrench that has pins that fit the upper pulley on a /6. Its used to hold the unit in place while you tighten the nut

Sounds like you are looking for tool P208. Originals sell for $ 100-150 or you can buy a repro for about $ 40. Pelican carries them.

Looks like Pelican the best option

Made my own wrench for $10!

http://www.914world.com/bbs2/index.php?sho...=242851&hl=

No! You don't want a P208, the 3.0 pulley is different.

For a 3.0 you need a P209, BTW this holds the pulley, then you also need another wrench (like patssle made) for the nut.
http://www.pelicanparts.com/cgi-bin/ksearc...er=PEL-TOL-P209



Also if you have the pulley for the 2nd the belt (smog pump?) you might want to get this pulley as it would make life a lot easier.
http://www.pelicanparts.com/cgi-bin/ksearc...106-208-00-M100