76 ford f250 heater core help?

I need to replace the heater core in my 76 ford or at least I think from my guess it is that. When I start it in morning (even in this warm weather) the windshield will steam up and it smells like anti freeze in the cab and motor gets hot fast. That is the heater core right? And also, if it is the heater core, it's just under the passenger side dash right? Thank you very much in advance any help is greatly appreciated!

Read more: 76 ford f250 heater core help?