Hi there - thought my experiences might help.
I am running a stroker (408) Windsor in my (UK) Crendon. When I installed the
oil cooler, I looked up several previous threads about what dia lines to run, and size of fittings to use, since I have fairly long piping runs and wanted to avoid a pressure drop problem. I used all dash 12 aeroquip fittings (NOT the forged ones which have pressure drop issues) and hose, with a Mocal 235 mm wide 13 row cooler.
One area I had to attend to was the
oil take-off sandwich plate, where I opened up the
oil passages with a die grinder. Without this the internal passges would have severely restricted oil flow, no matter what size piping I used.
Result is 50 psi at tickover, 60 - 65 psi from 3000rpm up, hot. I am using valvoline racing oil, 20W-50W, non
synthetic, which is a vast improvement on the oils I tried previously.
hope this helps
Wilf