They right there when you pull the intake manifold, and GirlBear on the Blazer forum did the job not too long ago.
The advice that she got is located here
http://www.automotiveforums.com/vbul...ntake+manifold
She drew up a pic for someone else, buy I haven't found the thread yet.
Check out your cam and be prepared to change it at the same time.
You might want to anyways, to 1 more suited to your driving style.
And of course the timing chain should be changed with a new cam, but that's it.