Hi Jeff;
The cores are from a late 90's Ford F-150. At the time most people were using the Harrison cores from GM. I had both a did flow tests on both and found slightly better flow through the Ford cores. And there were significantly more available at our local auto-wreckers.
But way back, I flew through a hail storm on short final and the rads looked like I'd hit them with a ball-peen hammer. I spent a lot of time straightening the fins but it seemed that I'd lost some efficiency, so with this rebuild I replaced them and I discovered that late 90's F-150's are not so common in the junk yards anymore.
I did modify the in/outlets as they were far too small. I drilled a 1" hole into the place of the original inlet plumbing, then used a die grinder to open up the end tank passage. I welded closed the old outlet and drilled a 1" outlet at the opposite end, using a die-grinder at this tank as well. The final result is a 3-pass core.
The fittings were made from 1" electrical aluminum conduit pipe. It is cheap and easily found (lots of scrap pieces at work), but is strong, easy to bend with the right tools and easy to weld. The bead on the end was simply made by welding a bead around the end -- crude but effective as the seal is made by the clamp on the smooth surface. The OD of this is 1.25"
All the hoses are 1.25". They are all automotive hoses and were found by going to an auto parts store that has all of their hoses hanging on a wall out front so I spent a few hours looking for a few hoses that had a combination of the right bends and curves in the correct diameter that I could cut and piece together the configuration that I needed for my desired routing. I only ended up with a single splice piece.
The one exception to the diameter is the Laminova which has a 1.5" diameter, but I was even able to find hoses that went from 1.5" to 1.25" in the shape I was looking for.
Todd