You're right.

Although on a big block, I think the problem is the worst of all. There's a lot of residual heat in all that cast iron, and it takes a LONG time to cool down. So if you drive like a cop, and then immediately shut down, it just bakes. And like I said, with a bigger, heavier engine, the problem is worse.

My 78 cop car (400) wasn't too dirty when I took it down. I have a 77 cop car (also 400), that looked like the canadian oil sands under the valve-covers. Obviously that car was beat hard and probably never allowed to cool before shut down. Needless to say, they both had the factory oil coolers.

Turbocharged cars also have this problem, although the better ones will continue to pump oil after shut down - sometimes by means of a turbo timer.

That's also a good observation about the orifice size. If I'm not mistaken, the return hole through the fuel pump bolt is rather small, maybe a 1/16" or 3/32" by memory. It gets the job done for factory HP levels though, and something bigger would start to compromise pressure, I'm sure.

Personally I need to figure out something for my 500" stroker, and I'd like to keep it looking as stock as possible. I plan to route upper head oiling through the rear of the block to save main and cam oiling, so I will already be back there with plumbing. Also want a thermostatic control so it doesn't keep the oil too cool. An engineering challenge