Thanks to all, esp. Greengas.
Father-in-law finished removal and tear-down of the 1.5 l carb'd engine from my sons 1988 I-Mark. Rod bearings didn't have visible wear, but #2 was around 3 thou clearance, rather than the 2.2 or similar spec'd.
Can't get 1 thou oversize bearings for that engine (which I was thinking about, before they had the crank out and measured it out-of-round...)
Got the crank turned 10 under, got the oversized bearings and rings. Knock is GONE!! (car still sounds and runs great, just without the extra racket...)
Down side: Cheap gasket set had a crappy rear seal. Oil was dripping so fast that it was almost running out.... Sigh. (and worse words). Out with the motor again, get a better seal on order.....
Also, f-in-law noted that the rockers and rocker shafts are quite obviously worn, so we can start the search for some good used parts there.... In any case, it will run a long time with what's there.
Again, thanks to all for help! dan