Ended up plumbing in a Derale thermostatically controlled oil cooler. Didn't want one without control as you can get the oil too cool when temps are below freezing.
Bought this radiator:
https://www.amazon.com/dp/B0932HHFYZ...roduct_details
It is made in China, but fit and finish is really nice. It is a true four row core.
The only mod I had to make was to the two small pads on the top retainer. The tanks are a lot bigger on this one than the one I had in it. Had to elongate the slots.
Easy. Curiously, the bottom pads were fine, as the slots were already a lot longer than the ones on the top. My water pump had started leaking slightly out the weep hole, so did the radiator and WP at the same time. Did this Sunday nite after getting the Corvette body off the frame.
Only odd thing was it came with a 19 lb. cap. I tested it with my old Stant tester, and sure enough, it pegged. I went ahead and used the 15 lb. cap from the old radiator.
Anyone need a free aluminum / plastic radiator that fits a 68 El Camino. It never overheated even on a 100 degree day UNLESS I was towing. Single row one inch tubes.
Will list it on the pay it forward ads.