some updates and requests for help:

after some research, i think crank position sensor is integral in these 2.4 89+ distributors.

so i broke down and swapped the whole donor distributor in. as others before me, had some challenges getting it in the right tooth. i *think* what i realized is that you have to align the rotor to #1 plug at TDC *when the housing is in fully-retarded position*. if you try doing it when the alignment bolt is at the notch (which is close to where the base timing will be), then you easily get a tooth off.

unfortunately, the situation is unchanged with the new distributor. it times to 7deg BTDC when the notch is just about aligned with the bolt. however, backfires and carbonizes the sparkplug. when maximally advance the distributor, it runs much better -- but the advance is way off.

on another forum got the suggestion that advancing timing has side-effect of leaning mix, so perhaps rather than a timing issue this is just a symptom of an underlying running-rich issue. again, having (i think) ruled out the fuel pressure regulator, and with good compression readings, what could be causing rich mix?

thanks folks!