[oil pan 4]

I was actually going to get a smaller more compact heat exchanger.
Then I found a flow and pressure drop chart.
Turns out a 10 plate 3x8 inch HX is only good for about 5 or 6 GPM, perfect for a small 4 cylinder engine and probably most V6 engines.
20 plates is good for 10 to 12gpm, that could work for around 90% of all non towing applications.
The 30 plate like I have is good for up to 15 to 18 gpm. The max flow on small block Chevy and big block Chevy engines is between 20 and 25 gpm.
So the 30 plate should be able to handle all the oil flow about 99.99% of engine run time.
If the oil cooler can't handle the flow the oil cooler adaptor bolted on to emgine block has a pressure differential by pass built in so some of the oil just won't go through the cooler.
If I didn't have a cooler and was going to buy new I would get the 20 plate on account of it being cheaper, lighter and smaller.

Based on the size of my 30 plate HX versus pretty much all the oil coolers I have seen I don't think they exchange that much heat.
The plate surface area of this cooler is probably about 6 to 8 times more than what I have seen on 4 cylinder engines. Sure the oil doesn't over heat, but it also doesn't warm up that fast either.
This 30 plate cooler is at least double the size of what is stock on my diesel engine.
The only time I have seen a cooler about this size was on old Detroit diesel 6-71 engines.
I usually over do stuff, this is no exception.

My operating envelope in new Mexico is from -16°F to 0°F in winter, that is what I, my self have personally seen so it may get even colder than that. In summer up to 104°F here and 111°F a little south of here.