Lots of good information on the Wallace Racing site. It is a frame page and only works correctly for me using Internet Explorer.
On the home page click on "Enter"
On the next page click on the "Info" link on the left
Then select the "engine codes" page and that should get you well on your way to identifying your engine.
Also, if you haven't found them yet, check out Performance Years
and Classical Pontiac
. Between those two sites, it is quite possible that you will find a previous owner or someone who has actually worked on the car you own.