Thanks.
I'll also be using insulation tape, to seal the airflow, and isolate the core from case vibrations: I hate rattles!
I had to cut ~1/4 into the crossbar of my case, to allow the core's bottom tanks to sit lower. Now the finned area fits exactly within the size of the back opening (~6" by ~8"). I should have pics sometime next week.
If I had more time/patience/tools, I would have trimmed that opening, so that the core sits ~1/4" outside the back of the case. I need more space for the blower, but not that much space! BTW the heatercore isn't perfectly square...
Now I have to figure out the exact shape of that fiberglass shroud
