I installed new wire at sender, and spliced into old wire by firewall; near the block, the old wire was brittle, with bare metal showing through in a few areas. Next, I cleaned off area where dummy light plugs into instrument panel.

Oil light glows when key is turned in first position, goes out when car is fired up. No flickering, though I haven't revved the engine up yet because I don't know true oil pressure at this point. Oil pressure gauge not working correctly this morning, reading 80 PSI at idle (!) while yesterday it was showing 40 PSI.

Gonna buy a gauge this afternoon, and get a better idea of what my oil pressure actually is. Oh yeah, no more smoke pouring out of tailpipe.