hey nick
look for that key way at the local parts house
( napa, autozone, abc )or speed shops and some engine rebuilder will sometimes hook ya up for a buck or two.
the speed shops my not have it listed for the older pontiac motors...but some chevy - v6 use the same size. (excuse the bad word ^^^^)

timing marks for the pont. should be cam dot at the bottom ( 6 o'clock ) and crank dot at the top ( 12 o'clock ).
i saying all this for the 350 to 455 if its a 6 cyl then i have not a clue and your are back where you started.