slant is running hot

James, the fish tape is correct... after I pulled the top tank off I had the problem of finding something that was rigid enough to push out the crap and thin enough to fit...enter the fish tape...I did have to cut then end off to make it fit thru the tiny passages but it worked like a charm

As for the heater core being plugged up...I agree that it is an indicator of how bad the crud in the system is, AND if the heater core is plugged, then so is the rad.....

When you do get a new radiator..check into installing a filter in the upper hose.
Something like this. (for the sake of not clogging up a new part)
http://neptune.spacebears.com/cars/stories/sctefba.html