I've seen my SVX smoke (once after a long trip, then sitting idle for 3 days, she smoked a lot on a startup.)

Run a quick search I think others have seen occasional smoke. Could be PCV related.

The best magic potion is STP. It is, after all, "The racer's edge" (Good enough for Richard Petty, good enough for me!)

It has some zinc based stuff in it that can actually help "lubricate" when you get metal to metal contact. The "goo factor" is high which gets the oil pressure back up to a reasonable level.

In the Austin Healey world, it is known as "Camshaft bearing rebuild in a can."

In my old truck, a pro-wrench gave 'er 1,000 miles to live back at 148,000 miles. She now has 221,000. She still clanks and generally sounds terminal at low rpms. The oil pressure is "marginal" at best. Is it the STP or the synthetic oil that prevented any additional damage? I don't know. I do know that it still runs great. I expect it to make it to 248,000.

I wouldn't put anything but synthetic engine oil in your SVX. It smokes...so what? Does it pass smog tests? Drive it. What if there isn't anything wrong with your engine internals and it turns out to be somthing relatively minor like a PCV valve or something?