Heater core r/r
Well it seems I'm a little late on the scene here. However, it's not that easy to r/r a heater core on these truck. Not difficult mine you but just a pain in the behind.
I will give you my experience and you can go from there.
First off pull off the hood, then the passengers side hood hinge. Next your going to have to remove the passengers side inner fender to access all the bolts. This is the reason that almost all of these trucks either don't have the bottom outside bolt not installed or the ear is broken off. once this is done then you can remove the bolts to the blower housing and pull it off the firewall. Once you get it off them you can clean the years of crap stored in your cowl out of there and then remove the clamps that hold your heater core into the blower motor housing. reinstall in reverse order, oh you'll probally find out that almost all of the nut clips for the inner fender will need replaced because they must be soemthing like single use clips, they self destruct after you try and get them out. Replace them know and all is well..
Hope this helps and sorry that it was late....