School's out, now back to the truck...

[hotrodrookie]

I havent got to work on my truck for what it seems like forever, but today I started doing some more sheet metal work. I plan on eventually swapping in a 5.3 vortec so I plan on using a gas tank under the bed. So today I filled the gas tank hole in the side of the cab. I want to begin filling the holes in the firewall but Im not sure which ones I am going to need, "i havent done this before". So Im thinking that im not going to use the original heater but when i find a motor donor truck id like to retrofit all of its heater and a/c into mine. Could any of you guys that have smoothed your firewalls post pics and let me know what you did for hoses or wires that would have gone through the original holes. Thanks
rookie..