Good advise mitch,
I just pulled both heater cores out of my wife's expedition on thanksgiving week. It was full of stop leak and gunk. Having to pull the dash was the most intimadating part.
So I'm guessing I have to do the same on the Capri to change it out.
Yeah it's a job since it's in the center pretty much. I doubt it's related to the stink if your fan isn't blowing. Heater cores can be back flushed as the whole cooling system. The only problem there is if someone got to scraping some gaskets on another repair and it got in the cooling system them little pieces of gaskets will hang up in the little channels in the core. There is no getting them out. Roosport still sells new cores.
The heater hoses are still readily available. They are your normal slide on one's about $10 a piece.
That little bypass hose under the distributor on mine blew right after I got my car. Cost me a head job and new radiator. I went ahead and changed the pump and all the hoses. Something to consider if one hose is bad. Go ahead and change them all because the residual effect is expensive.
There's a good thread here somewhere on the heater core. You might search it out. I think it has pictures and everything you need to know. Then of course there's the online manual at TechCapri.