Dash apart, replacing heater core...what else?

Id pull all the a/c stuff and id check wires while i was under there. I did my heater core then i put a radio in my car and it wasnt working so i changed the fuse and smoke started to come out from under the dash. Two wires had corroded and were shorting out now its a big headache.
 
The hard part was getting the dash out far enough to get access to the core. I can not figure out what was holding it on the driver's side. I had everything disconnected, but something kept it in place. Then I took off two the the three bolts holding the core's box top on, and ended up breaking the top. But it worked out fine, because putting the new core in was a lot easier. All I did was put some poxy on where it broke and it seems to be fine. Just putting on some silcone to make a better seal.

Overall, I didn't think it was really hard...maybe a 7/10. Mostly just time consuming. I used this site and it helped a lot,
http://www.mustangmonthly.com/howto/5652/index.html

Just a tip, when you try and open the heator core lid, just use a hacksaw blade and make a nice even cut. The core should just slip in then!