I can tell you it's a pain in the ass... When I painted my cam cover i accidentally pulled all 4 of them out. UGH!
Here's how I got them in: (refer to the manual for specifics, I'll reference the firebolt manual available for download on the top of the page)
-Rotate the entire engine forward so you can get at the front head
-Remove the cam cover
-Remove the Rocker Box Assembly (page 3.46) You really don't need to completely remove it, the idea here is to get it so you can easily move the front lifters out of your way.
-Rotate the engine till the back cylinder is at TDC of the compression stroke (both valves closed, pull the spark plugs if you are having trouble)
-Line up and install the cams. This is where I get a little fuzzy, I can't remember how the timing marks worked out. I believe they lined up perfectly while the rear cylinder has both valves closed. You may have to play around to get it right. (p 3.88 has the details you need)
-Once the cams are installed rotate the engine so both valves on the front cylinder are closed, then you should be able to put the top end back together. PAY ATTENTION TO YOUR TORQUE SPECS!
All I know is that I didn't have to remove the pushrods and lifters like the manual says. Removing the front rocker assembly was all I had to pull to get the cams in.
